Våre poenggivende vitenskapelige publikasjoner
Listen inneholder vitenskapelige artikler, bøker og kapitler som er publisert i poenggivende tidsskrifter og forlag. Det nasjonale registeret over vitenskapelige tidsskrifter er utgangspunktet for hvilke vitenskapelige publikasjoner som gir uttelling i finansieringssystemet. Listen er sortert etter siste registrerte publikasjon
Vitenskapelig – Impacts of climate change adaptation options on soil functions: A review of European case‐studies
Ahmad Hamidov, Katharina Helming, Gianni Bellocchi, ...
Soils are vital for supporting food security and other ecosystem services. Climate change can affect soil functions both directly and indirectly. Direct effects include temperature, precipitation, and moisture regime changes. Indirect effects include those that are induced by adaptations such as irrigation, crop rotation changes, and tillage practices. Although extensive knowledge is available on the direct effects, an understanding of the indirect effects of agricultural adaptation options is less complete. A review of 20 agricultural adaptation case‐studies across Europe was conducted to assess implications to soil threats and soil functions and the link to the Sustainable Development Goals (SDGs). The major findings are as follows: (a) adaptation options reflect local conditions; (b) reduced soil erosion threats and increased soil organic carbon are expected, although compaction may increase in some areas; (c) most adaptation options are anticipated to improve the soil functions of food and biomass production, soil organic carbon storage, and storing, filtering, transforming, and recycling capacities, whereas possible implications for soil biodiversity are largely unknown; and (d) the linkage between soil functions and the SDGs implies improvements to SDG 2 (achieving food security and promoting sustainable agriculture) and SDG 13 (taking action on climate change), whereas the relationship to SDG 15 (using terrestrial ecosystems sustainably) is largely unknown. The conclusion is drawn that agricultural adaptation options, even when focused on increasing yields, have the potential to outweigh the negative direct effects of climate change on soil degradation in many European regions.
Vitenskapelig – Modelling grass yields in northern climates – a comparison of three growth models for timothy
Panu Korhonen, Taru Palosuo, Tomas Persson, ...
During the past few years, several studies have compared the performance of crop simulation models to assess the uncertainties in model-based climate change impact assessments and other modelling studies. Many of these studies have concentrated on cereal crops, while fewer model comparisons have been conducted for grasses. We compared the predictions for timothy grass (Phleum pratense L.) yields for first and second cuts along with the dynamics of above-ground biomass for the grass simulation models BASGRA and CATIMO, and the soil-crop model STICS. The models were calibrated and evaluated using field data from seven sites across Northern Europe and Canada with different climates, soil conditions and management practices. Altogether the models were compared using data on timothy grass from 33 combinations of sites, cultivars and management regimes. Model performances with two calibration approaches, cultivar-specific and generic calibrations, were compared. All the models studied estimated the dynamics of above-ground biomass and the leaf area index satisfactorily, but tended to underestimate the first cut yield. Cultivar-specific calibration resulted in more accurate first cut yield predictions than the generic calibration achieving root mean square errors approximately one third lower for the cultivar-specific calibration. For the second cut, the difference between the calibration methods was small. The results indicate that detailed soil process descriptions improved the overall model performance and the model responses to management, such as nitrogen applications. The results also suggest that taking the genetic variability into account between cultivars of timothy grass also improves the yield estimates. Calibrations using both spring and summer growth data simultaneously revealed that processes determining the growth in these two periods require further attention in model development.
Vitenskapelig – Nitrogen balances and nitrogen use efficiency in the Nordic countries
Anne Falk Øgaard, Marianne Bechmann
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Vitenskapelig – Directional versus total reflectance spectroscopy for the in situ determination of lycopene in tomato fruits
Leonardo Ciaccheri, Lorenza Tuccio, Andrea A. Mencaglia, ...
Non-destructive tools for evaluating the lycopene content in tomatoes are of great interest to the entire fruit chain because of an increasing demand for beneficial health products. With the aim of developing compact low-cost reflectance sensors for lycopene determination, we compared Partial Least Squares (PLS) prediction models by using either directional or total reflectance in the 500–750 nm range. Directional reflectance at 45° with respect to the LED lighting direction was acquired by means of a compact spectrometer sensor. Total reflectance was acquired through a 50-mm integrating sphere connected to a spectrometer. The analysis was conducted on two hydroponic greenhouse cultivated red tomato varieties, namely the large round ‘Dometica’ (average diameter: 57 mm) and the small cherry ‘Juanita’ (average diameter: 26 mm). For both varieties, the spectral variance of directional reflectance was well correlated to that of total reflectance. The performances of the PLS prediction models were also similar, with R2 of cross-validation between 0.73 and 0.81. The prediction error, relative to the mean lycopene content of full ripe tomatoes, was similar: i.e. around 16–17% for both varieties and sensors. Our results showed that directional reflectance measured by means of portable, low-cost and compact LED-based sensors can be used with an adequate precision for the non-destructive assessment of lycopene in tomatoes.
Vitenskapelig – A sensible climate solution for the boreal forest
Rasmus Astrup, Pierre Y. Bernier, Helene Genet, ...
Climate change could increase fire risk across most of the managed boreal forest. Decreasing this risk by increasing the proportion of broad-leaved tree species is an overlooked mitigation–adaption strategy with multiple benefits.
Vitenskapelig – ADAPTATION TO CLIMATE CHANGE: IMPACT OF CAPACITY BUILDING, INDIA
Krishna Reddy Kakumanu, Yella Reddy Kaluvai, M. Balasubramanian, ...
Climate change adversely affects the determinants of agriculture. Adaptation serves as an important strategy to reduce the adverse effects of climate change (variability) and vulnerability of the people. Adaptation through an innovation programme was implemented for 4 years during 2012–2016 to improve the adaptive capacity in agriculture and the water sectors through capacity building and implementation in the Krishna River Basin, India. Primary data were collected from 178 farm households of the Nagarjuna Sagar Project command area covering both adopters and non‐adopters of water‐saving interventions from the study area. The double difference method was used to analyse the impact of adaptation through capacity building and implementation. The water‐saving interventions include alternate wetting and drying (AWD) in rice, a modified system of rice intensification (MSRI) and direct seeding of rice (DSR). The capacity building and water saving increased crop yields by 0.96, 0.93 and 0.77 t ha−1 through AWD, MSRI and DSR respectively. The three practices have increased farmers’ income and decreased the cost of cultivation in DSR by Rs.11 000 (US$169) ha−1. The methods can be more focused in canal commands on a larger scale for equal distribution of water to all the head, middle and tail‐end regions.
Vitenskapelig – Peat replacement in horticultural growth media: the adequacy of coir, paper sludge and biogas digestate as growth medium constituents for tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.)
Astrid Solvåg Nesse, Trine Aulstad Sogn, Trond Børresen, ...
Purpose: Due to environmental concerns, efforts are made to replace the use of peat in horticultural growth media by organic wastes. Four growth media were prepared with the purpose of achieving adequate physical and chemical properties for plant production. Materials and methods: Growth media prepared from mixtures of coir (C) and paper sludge (P), respectively, with two biogas digestates from food waste (D1 and D2), were tested. These mixtures, 20% D1 or D2 + 80% C or P (v/v), were evaluated as growth media for tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.). Results and conclusion: The growth media were all physically stable during the growing period, provided all the macronutrients and most of the micronutrients necessary for plant growth, adequate pH conditions, as well as an adequate electrical conductivity. The mixture of D2 and P produced the highest biomass compared to a mineral fertilised peat (control), with a biomass production of 76% of the control for lettuce and 54% for tomato. Causes for the biomass reduction relative to the control may be related to ammonium toxicity effects, and/or limited plant-available water. The digestates, particularly D1, seemed also to have a phytotoxic effect on the germination.
Vitenskapelig – Mitigating particle and nutrient losses via subsurface agricultural drainage using lightweight aggregates
Jarle Tommy Bjerkholt, Jens Kværner, Petter D. Jenssen, ...
The awareness of sediment and nutrient loss from non-point sources are of increasing environmental concern as measures to reduce point source inputs to surface waters have been introduced. Mitigation efforts to reduce loss of particles and nutrients from agriculture in Norway and other countries have mainly focused on surface runoff, whereas sub-surface drainage has received little attention. However, research has shown that the sub-surface field drains are transporting both sediment and nutrients rapidly to the watercourses. Despite these established facts there has been little development of measures to reduce these losses. This article describes how Lightweight Aggregates (LWA), Leca®, can mitigate some of the environmental challenges connected to sub-surface field drains. A field experimental project was performed to assess the effects on drainage water quality hydrological performance and functionality of drainage systems based on Lightweight Aggregates compared to traditional pipe drains. Registrations of the performance of the systems were done in two separate periods, 1992–1993 and 1999–2000. After 2000 no measurement programme has run. The functionality of the drainage systems was registered in connection to ordinary farming activity. In 1999–2000 LWA drains showed particularly good performance with regard to reducing the content of Phosphorus, 40–90 % reduction in Total-P. The drainage water from the LWA drains contained less than half the amount of suspended solids compared to traditional pipe drains. The results from 1993 showed no significant difference between LWA drains and pipe drains with respect to Nitrogen. The results from 1999/2000 showed higher loss of Nitrogen through pipe drains with no envelope compared to all other systems. LWA drains may be particularly useful in reducing particles and nutrient loads from cultivated flat drained areas adjacent to environmentally sensitive and ecologically important water ecosystems. Further investigations are recommended to optimise the design of LWA drains.
Vitenskapelig – Building Farm-Level Capacities in Irrigation Water Management to Adapt to Climate Change
Krishna Reddy Kakumanu, Yella Reddy Kaluvai, Udaya Sekhar Nagothu, ...
Climate change characterized by global warming has become a hotspot of research in recent years for water resources, agriculture,ecology and other disciplines. In India, studies have shown an increasing trend in surface temperature, with decreasing trends inrainfall. Farmers are also more affected by the climate variability which has a serious influence on their production and income.The climate change and adaptation (ClimaAdapt) programme was implemented from 2012 to 2016 to build farm-level capacitiesand enhance the adaptive capacity of the agricultural and water sectors in the Krishna basin of Andhra Pradesh and Telanganastates. Water-saving interventions such as direct seeded rice, a modified system of rice intensification and alternate wetting anddrying (AWD) of rice were implemented in a cluster approach and enhanced water productivity. The training and implementationprogrammes increased the adaptation and awareness of farmers. Water measurements were carried out by usingflumes andultrasonic sensors. The area under direct seeded rice has increased to 64% in the study district and 77% of the trained farmersare adopting the practice. Capacity building, implementation and science–policy linkages are the key pillars of the programmeto improve the adaptive capacity and scaling-up of water management practices.
Vitenskapelig – Plantetilgjengelig fosfor i kalkfelt avløpsslam
Anne Falk Øgaard, Lasse Vråle, Martin Mengede
Sewage sludge is a significant phosphorus resource that should be better utilized in the plant production than today. However, phosphorus in sludge produced after precipitation with aluminium and iron coagulants have low plant availability. This article presents results from plant growth experiments where plant available phosphorus in lime precipitated sewage sludge from Bokerøya and Skådevika wastewater treatment plants was studied. Both wastewater treatment plants normally use iron as coagulant aid, but Skådevika produced in addition a sludge to the experiments without using iron. The growth experiments included a pot experiment in greenhouse with three harvests of Italian ryegrass (Lolium multiflorum) and a two-year field experiment in cereals in Southeast Norway. The results showed that precipitation with lime gives a sludge with higher plant availability of phosphorus than what is earlier found for aluminium/ iron precipitated sludge. This was special the case with moderate use of iron as coagulant aid.
Vitenskapelig – Identifying precipitation uncertainty in crop modelling using Bayesian total error analysis
Xiao Huang, Shaoqiang Ni, Chaoqing Yu, ...
Precipitation is an important source of soil water, which is critical to crop growth, and is therefore an important input when modelling crop growth. Although advances are continually being made in predicting and recording precipitation, input uncertainty of precipitation data is likely to influence the robustness of parameter estimate and thus the predictive accuracy in soil water and crop modelling. In this study, we use the Bayesian total error analysis (BATEA) method for the water-oriented crop model AquaCrop to identify the input uncertainty from multiple precipitation products respectively, including gauge-corrected grid dataset CPC, remote sensing based TRMM and reanalysis based ERA-Interim. This methodology uses latent variables to correct the input data errors. Adopting a single-multiplier method for precipitation correction, we simulate maize growth in both field and regional levels in China for a range of different possible climatic scenarios. Meanwhile, we use the average of multiple products for model driving in comparison. The results show that the BATEA method can consistently reduce uncertainty for crop growth prediction among different precipitation products. In regional simulation, the improvements for the three products are 1%, 7.3% and 2.8% on average in drought scenarios. These results imply the BATEA approach can be of great assistance for crop modeling studies and agricultural assessments under future changing climates.
Vitenskapelig – A dynamic agricultural prediction system for large-scale drought assessment on the Sunway TaihuLight supercomputer
Xiao Huang, Chaoqing Yu, Jiarui Fang, ...
Crop models are widely used to evaluate the response of crop growth to drought. However, over large geographic regions, the most advanced models are often restricted by available computing resource. This limits capacity to undertake uncertainty analysis and prohibits the use of models in real-time ensemble forecasting systems. This study addresses these concerns by presenting an integrated system for the dynamic prediction and assessment of agricultural yield using the top-ranked Sunway TaihuLight supercomputer platform. This system enables parallelization and acceleration for the existing AquaCrop, DNDC (DeNitrification and DeComposition) and SWAP (Soil Water Atmosphere Plant) models, thus facilitating multi-model ensemble and parameter optimization and subsequent drought risk analysis in multiple regions and at multiple scales. The high computing capability also opens up the possibility of real-time simulation during droughts, providing the basis for more effective drought management. Initial testing with varying core group numbers shows that computation time can be reduced by between 2.6 and 3.6 times. Based on the powerful computing capacity, a county-level model parameter optimization (2043 counties for 1996–2007) by Bayesian inference and multi-model ensemble using BMA (Bayesian Model Average) method were performed, demonstrating the enhancements in predictive accuracy that can be achieved. An application of this system is presented predicting the impacts of the drought of May–July 2017 on maize yield in North and Northeast China. The spatial variability in yield losses is presented demonstrating new capability to provide high resolution information with associated uncertainty estimates.
Vitenskapelig – Evaluation of a Petroleum-Derived Spray Oil for Control of Microdochium Patch and Turfgrass Spring Performance on Nordic Golf Greens
Trygve S. Aamlid, Oiva Niemelainen, Klaus Paaske, ...
Greenkeepers are looking for alternatives to fungicides for control of turfgrass diseases. Our objective was to evaluate a petroleum- derived spray oil with a blue-green pigment for control of Microdochium patch/pink snow mold (Microdochium nivale) on golf course putting greens with various durations of snow cover. The spray oil was applied at rates 27 or 54 L ha–1 every third week from late August or September to December, either alone, in tank mixture with potassium phosphite (3 kg PO3 ha–1) or in tank mixture with half rate of fungicides approved for turf, in five 1-yr trials in the Nordic countries. The oil was as effective or more effective than fungicides and gave, on average, 94 and 98% disease control at rates 27 and 54 L ha–1, respectively. Tank mixtures with half rate of prochloraz + propioconazole and fludioxonil did not increase disease suppression in a trial with 79 d snow cover. Phosphite reduced disease severity in one trial only and did not improve disease control or turfgrass quality when tank-mixed with the oil. The pigment in the spray oil was highly persistent and improved turfgrass greenness except in a trial where the combination of oil and ice cover gave a transitory black color at ice melt. Another trial with long snow cover showed a drop in turfgrass quality in spring as the spray oil prevented normal green-up. In conclusion, this research shows that a spray oil has the potential to reduce fungicide use on Nordic golf courses.
Vitenskapelig – Carbonic anhydrase activity in seaweeds: overview and recommendations for measuring activity with an electrometric method, using Macrocystis pyrifera as a model species
Pamela A. Fernández, Michael Roleda, Ralf Rautenberger, ...
Carbonic anhydrase (CA) plays an important physiological role in all biological systems by accelerating the interconversion of CO2 and HCO3 −. In algae, CA is essential for photosynthesis: external CA (CAext) dehydrates HCO3 −, enhancing the supply of CO2 to the cell surface, and internal CA (CAint) interconverts HCO3 − and CO2 to maintain the inorganic carbon (Ci) pool and supply CO2 to RuBisCO. We frst conducted a literature review comparing the conditions in which CA extraction and measurement have been carried out, using the commonly used Wilbur–Anderson method. We found that the assay has been widely modifed since its introduction in 1948, mostly without being optimized for the species tested. Based on the review, an optimized protocol for measuring CA in Macrocystis pyrifera was developed, which showed that the assay conditions can strongly afect CA activity. Tris–HCl bufer gave the highest levels of CA activity, but phosphate bufer reduced activity signifcantly. Bufers containing polyvinylpyrrolidone (PVP) and dithiothreitol (DTT) stabilized CA. Using the optimized assay, CAext and CAint activities were readily measured in Macrocystis with higher precision compared to the non-optimized method. The CAint activity was 2×higher than CAext, which is attributed to the Ci uptake mechanisms of Macrocystis. This study suggests that the CA assay needs to be optimized for each species prior to experimental work to obtain both accurate and precise results.
Vitenskapelig – Dissolved carbon in a large variety of lakes across five limnetic regions in China
Kaishan Song, Zhidan Wen, Yijun Xu, ...
Dissolved carbon in lakes play a vital role in the global carbon cycling. The concentration and dynamics of lake dissolved carbon can be influenced by both the surrounding landscape and a combination of physical, chemical and biological processes within the lakes themselves. From 2009 to 2016, we conducted a large-scale assessment of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) in 249 lakes across a diverse range of climatic, geopedologic, topographical and hydrological conditions in five Chinese limnetic regions: the East Limnetic Region (ELR), the Northeast Limnetic Region (NLR), the Inner Mongolia-Xinjiang Limnetic Region (MXR), the Yungui Limnetic Region (YGR), and the Tibet-Qinghai Limnetic Region (TQR). We found that the density of the organic matter in the soil in the surrounding landscape plays an important role in the DOC and DIC in lake water, as was evidenced by the high DOC and DIC levels in the NLR, where the soil is respectively organically rich. Conditions in the arid and semi-arid environments (i.e. TQR and MXR) have created a number of brackish/saline lakes and here we found that, DOC and DIC levels (median: 21.79 and 93.72 mg/L, respectively) are significantly higher than those in the freshwater lakes (median: 5.80 and 29.38 mg/L). It also appears to be the case that the trophic state of freshwater lakes influences the spatial variation of DOC. This can be seen in the relationships between DOC and trophic state index (TSI) in agriculturally-dominated regions such as the ELR (R2 = 0.59, p < 0.01), NLR (R2 = 0.65, p < 0.001), and YGR (R2 = 0.78, p < 0.001). Additionally, a close relationship between DOC and DIC can be found in lake waters with different trophic states (eutrophic: slp = 0.63, R2= 0.69; mesotrophic: slp = 1.03, R2 = 0.65; oligotrophic: slp = 1.00, R2 = 0.64). This indicates that human activities influence the quantity and quality of dissolved carbon in inland water across China. This study is able to provide insights regarding the potential effects of climate change and changes in land-use upon the amount of dissolved carbon in lake water.
Vitenskapelig – Impact of Multiple Ecological Stressors on a Sub-Arctic Ecosystem: No Interaction Between Extreme Winter Warming Events, Nitrogen Addition and Grazing
Stef Bokhorst, Matty P. Berg, Guro Kristine Edvinsen, ...
Climate change is one of many ongoing human-induced environmental changes, but few studies consider interactive effects between multiple anthropogenic disturbances. In coastal sub-arctic heathland, we quantified the impact of a factorial design simulating extreme winter warming (WW) events (7 days at 6–7∘C) combined with episodic summer nitrogen (+N) depositions (5 kg N ha-1) on plant winter physiology, plant community composition and ecosystem CO2 fluxes of an Empetrum nigrum dominated heathland during 3 consecutive years in northern Norway. We expected that the +N would exacerbate any stress effects caused by the WW treatment. During WW events, ecosystem respiration doubled, leaf respiration declined (-58%), efficiency of Photosystem II (Fv/Fm) increased (between 26 and 88%), while cell membrane fatty acids showed strong compositional changes as a result of the warming and freezing. In particular, longer fatty acid chains increased as a result of WW events, and eicosadienoic acid (C20:2) was lower when plants were exposed to the combination of WW and +N. A larval outbreak of geometrid moths (Epirrita autumnata and Operophtera brumata) following the first WW led to a near-complete leaf defoliation of the dominant dwarf shrubs E. nigrum (-87%) and Vaccinium myrtillus (-81%) across all experimental plots. Leaf emergence timing, plant biomass or composition, NDVI and growing season ecosystem CO2 fluxes were unresponsive to the WW and +N treatments. The limited plant community response reflected the relative mild winter freezing temperatures (-6.6∘C to -11.8∘C) recorded after the WW events, and that the grazing pressure probably overshadowed any potential treatment effects. The grazing pressure and WW both induce damage to the evergreen shrubs and their combination should therefore be even stronger. In addition, +N could have exacerbated the impact of both extreme events, but the ecosystem responses did not support this. Therefore, our results indicate that these sub-arctic Empetrum-dominated ecosystems are highly resilient and that their responses may be limited to the event with the strongest impact.
Vitenskapelig – Genotyping of Festulolium Cultivars Involved in EUCARPIA Multi-site Trial Using DArT Markers and GISH
David Kopecký, Joost Baert, Susanne Barth, ...
A comprehensive set of Festulolium cultivars from on-going field trials in the Eucarpia network was characterised at the chromosome level using genomic in situ hybridization (GISH) and by Diversity Array Technology (DArT) markers. Both technologies were found to be complementary in describing the breeding history of the plant material. The genomic composition of the Lolium X Festuca cultivars varied from those that comprised equivalent proportions of their parental genomes to introgression lines where small chromosome segments of Festuca had been translocated onto Lolium chromosomes. The breadth of genotype combinations found within the grass cultivars described represents an important resource of genetic variations necessary to combat the diverse abiotic stresses encountered within Europe, including safeguards against prolonged exposure to harsh weather conditions. It is likely that in future plant breeding, genotyping will contribute to precision-transfers of targeted Festuca genes into Lolium germplasm in order to enhance resilience to climate change.
Vitenskapelig – Low crown rust resistance in Norwegian material of Lolium perenne and ×Festulolium
Liv Østrem, Torben Asp, Marc Ghesquière, ...
Norwegian cultivars and breeding materials of perennial ryegrass and Festulolium were planted at three locations in Denmark, France and Japan for test-ing of resistance against leaf diseases. In general, all plant materials were susceptible to crown rust. The highest incidence of rust attack occurred at the French site, which due to its climatic conditions might be the most suitable testing site for future scoring of similar plant material. Entries based on introgressed genetic materials from UK were most resistant towards crown rust. Crown rust resistance needs increased focus as a breeding objective in the Nordic region due to climate changes, which will most likely lead to increased infection of leaf diseases.
Vitenskapelig – Influence of fertilization on growth and generative parameters of two short day strawberry cultivars grown in substrate, and evaluation of analysing tools for leaf nitrate and potassium
Rolf Nestby, Tomasz Leszek Woznicki, Anita Sønsteby
We examined the influence of fertigation on vegetative and generative parameters of strawberry plants (Fragaria × ananassa Duch.) and evaluated rapid analysing tools for N and K in leaf tissue. The experiments were undertaken in an open polytunnel on “table top” with ‘Sonata’ and ‘Korona’ grown in 2-L pots filled with a peat-based soil mixture. The experimental design was a randomized plot with three replications. Plants were fertigated with EC levels of 0.5, 1.0, 1.5 and 2.0 mS cm-1, based on two stock solutions of 7.5 kg YaraLiva™ Calcinit and 7.5 kg Kristalon™ Indigo, both dissolved in 100 L of water. Percentage N and K in leaves differed between analysing methods, cultivars, EC and date. We found interactions between the cultivar and EC level and between date and cultivar for N and K in leaf. Analysing NO3- by a photometric method (PM) in a lab, and by Laqua twin (LT), showed significant interaction with N% of leaf dry matter (DM) only for LT (r2=0.36). N% increased with higher EC level, more for ‘Korona’ than for ‘Sonata’. LT K+ did not correlate with K% (r2=0.014). The number of crowns and runners increased for both cultivars up to EC 1.5, while the number of leaves was unaffected. Petioles were the shortest at the lowest EC. Flower initiation was earlier at low EC in both cultivars. In the following spring, the time to flowering and first harvest was reduced with the decreasing EC. The number of flowers per plant increased up to EC 1.5, but dropped strongly at EC 2.0 for ‘Korona’, while ‘Sonata’ had a gradual increase of flowers with the increasing EC, but the number was only a third of ‘Korona’, except at EC 2.0, where the amount was equal for both cultivars. The conclusion can be drawn that LT correlated better than ChlDualex with N in strawberry leaves. However, r2 was only 0.36 indicating that LT NO3- is a coarse management tool. LT K+ was not a promising tool for rapid K+ test in these experiments. ‘Korona’ seemed to benefit of higher N levels for both vegetative growth and generative development than ‘Sonata’ up to EC 1.5, but ‘Sonata’ reached a higher floral primordia development stage in early October.
Vitenskapelig – How private are Europe’s private forests? A comparative property rights analysis
Liviu Nichiforel, Kevin Keary, Philippe Deuffic, ...
Private forests are widespread in Europe providing a range of ecosystem services of significant value to society, and there are calls for novel policies to enhance their provision and to face the challenges of environmental changes. Such policies need to acknowledge the importance of private forests, and importantly they need to be based on a deep understanding of how property rights held by private forest owners vary across Europe. We collected and analysed data on the content of property rights based on formal legal requirements existing in 31 European jurisdictions. To allow a comparison across jurisdictions, we constructed an original Property Rights Index for Forestry encompassing five rights domains (access, withdrawal, management, exclusion and alienation). We documented substantial variation of the private forest owners’ rights, and notably to i) make decisions in operational management and the formulation of management goals, ii) withdraw timber resources from their forest, and iii) exclude others from the use of forest resources. We identified broad relations between the scope for decision making of private forest owners and jurisdictions’ former socio-political background and geographical distribution. The variation in the content of property rights has implications for the implementation of international environmental policies, and stresses the need for tailored policy instruments, when addressing European society’s rural development, the bioeconomy, climate change mitigation measures and nature protection strategies.
Vitenskapelig – Challenges of reducing phosphorus based water eutrophication in the agricultural landscapes of Northwest Europe
Roland Bol, Gerard Gruau, Per-Erik Mellander, ...
In this paper, we outline several recent insights for the priorities and challenges for future research for reducing phosphorus (P) based water eutrophication in the agricultural landscapes of Northwest Europe.We highlight that new research efforts best be focused on headwater catchments as they are a key influence on the initial chemistry of the larger river catchments, and here many management interventions are most effectively made. We emphasize the lack of understanding on how climate change will impact on P losses from agricultural landscapes. Particularly, the capability to disentangle current and future trends in P fluxes, due to climate change itself, from climate driven changes in agricultural management practices and P inputs. Knowing that, future climatic change trajectories for Western Europe will accelerate the release of the most bioavailable soil P. We stress the ambiguities created by the large varieties of sources and storage/transfer processes involved in P emissions in landscapes and the need to develop specific data treatment methods or tracers able to circumvent them, thereby helping catchment managers to identify the ultimate P sources that most contribute to diffuse P emissions. We point out that soil and aqueous P exist not only in various chemical forms, but also in range of less considered physical forms e.g., dissolved, nanoparticulate, colloidal and other particulates, all affected differently by climate as well as other environmental factors, and require bespoke mitigation measures. We support increased high resolution monitoring of headwater catchments, to not only help verify the effectiveness of catchments mitigation strategies, but also add data to further develop new water quality models (e.g., those include Fe-P interactions) which can deal with climate and land use change effects within an uncertainty framework. We finally conclude that there is a crucial need for more integrative research efforts to deal with our incomplete understanding of the mechanisms and processes associated with the identification of critical source areas, P mobilization, delivery and biogeochemical processing, as otherwise even highintensity and high-resolution research efforts will only reveal an incomplete picture of the full global impact of the terrestrial derived P on downstream aquatic and marine ecosystems.
Vitenskapelig – Impact of post-fire management on soil respiration, carbon and nitrogen content in a managed hemiboreal forest
Kristi Parro, Kajar Köster, Kalev Jogiste, ...
Boreal forests are an important carbon (C) sink and fire is the main natural disturbance, directly affecting the Ccycle via emissions from combustion of biomass and organic matter and indirectly through long-term changes in C-dynamics including soil respiration. Carbon dioxide (CO2) emission from soil (soil respiration) is one of the largest fluxes in the global C-cycle. Recovery of vegetation, organic matter and soil respiration may be influenced by the intensity of post-fire management such as salvage logging. To study the impact of forest fire, fire and salvage, and recovery time on soil respiration and soil C and N content, we sampled two permanent research areas in north-western Estonia that were damaged by fire: Vihterpalu (59°13′ N 23°49′ E) in 1992 and Nõva (59°10′ N 23°45′ E) in 2008. Three types of sample plots were established: 1) unburned control with no harvesting (CO); 2) burned and uncleared (BU); and 3) burned and cleared (BC). Measurements were made in 2013, 21 years after wildfire in Vihterpalu and 5 years after wildfire in Nõva. Soil respiration ranged from 0.00 to 1.38 g CO2 m−2 h−1. Soil respiration in the burned and cleared areas (BC) was not reduced compared to burned and uncleared (BU) areas but the average soil respiration in unburned control areas was more than twice the value in burned areas (average soil respiration in CO areas was 0.34 CO2 m−2 h−1, versus 0.16 CO2 m−2 h−1, the average soil respiration of BC and BU combined). Recovery over 20 years was mixed; respiration was insignificantly lower on younger than older burned sites (when BC and BU values were combined, the average values were 0.15 vs. 0.17 g CO2 m−2 h−1, respectively); soil-C was greater in the older burned plots than the younger (when BC and BU values were combined, the average values were 9.71 vs. 5.99 kgm−2, respectively); but root biomass in older and recently burned areas was essentially the same (average 2.23 and 2.11 kgm−2, respectively); soil-N was highest on burned areas 20 years after fire. Twenty years post-fire may be insufficient time for carbon dynamics to fully recover on these low productivity sandy sites.
Vitenskapelig – Fertilization and susceptibility to fruit cracking in plums (Prunus domestica L.)
Eivind Vangdal, Iren Lunde Knutsen, Kristin Kvamm-Lichtenfeld
European plums are susceptible to fruit cracking close to harvest. Heavy rainfall may lead to extensive damages leaving open wounds in the fruit flesh. In addition, cuticular fractures were found. Plum cultivar and stage of maturity are two major factors affecting the susceptibility to cracking. In order to reduce the plums’ susceptibility to cracking plum trees were treated with foliar fertilization during the growing season. Experiments included treatment with boron, calcium and nitrogen. Experiments including treatments with different levels of foliar fertilization did not show clear correlations between treatments and cracking in all cultivars. However, in some cultivars, more cuticular fractures were observed in fruits from nitrogen treated trees and less fractures in fruit from calcium or boron treated trees. In these experiments foliar fertilization with nitrogen, calcium or boron did not affect the amount of visible cracks in fruit significantly. Foliar fertilization is often shown to delay ripening. Even though fruit samples were picked at the same maturity stage, the effect of reduced cracking due to boron and calcium treatments could be partly an effect of differences in maturity. To make sure the fruits would develop fractures, unripe plum fruits on the trees were kept in a plastic bag with zip-lock and a few mL of water (to obtain 100% RH) for one week (from two to one week prior to estimated harvest date). In this way, the susceptibility of fruits on trees treated differently could be observed.
Vitenskapelig – Special delivery: scavengers direct seed dispersal towards ungulate carcasses
Sam Steyaert, Shane Frank, Stefano Puliti, ...
Cadaver decomposition islands around animal carcasses can facilitate establishment of various plant life. Facultative scavengers have great potential for endozoochory, and often aggregate around carcasses. Hence, they may disperse plant seeds that they ingest across the landscape towards cadaver decomposition islands. Here, we demonstrate this novel mechanism along a gradient of wild tundra reindeer carcasses. First, we show that the spatial distribution of scavenger faeces (birds and foxes) was concentrated around carcasses. Second, faeces of the predominant scavengers (corvids) commonly contained viable seeds of crowberry, a keystone species of the alpine tundra with predominantly vegetative reproduction. We suggest that cadaver decomposition islands function as endpoints for directed endozoochory by scavengers. Such a mechanism could be especially beneficial for species that rely on small-scale disturbances in soil and vegetation, such as several Nordic berry-producing species with cryptic generative reproduction.
Vitenskapelig – Land cover segmentation of airborne LiDAR data using stochastic atrous network
Hasan Asyari Arief, Geir Harald Strand, Håvard Tveite, ...
Inspired by the success of deep learning techniques in dense-label prediction and the increasing availability of high precision airborne light detection and ranging (LiDAR) data, we present a research process that compares a collection of well-proven semantic segmentation architectures based on the deep learning approach. Our investigation concludes with the proposition of some novel deep learning architectures for generating detailed land resource maps by employing a semantic segmentation approach. The contribution of our work is threefold. (1) First, we implement the multiclass version of the intersection-over-union (IoU) loss function that contributes to handling highly imbalanced datasets and preventing overfitting. (2) Thereafter, we propose a novel deep learning architecture integrating the deep atrous network architecture with the stochastic depth approach for speeding up the learning process, and impose a regularization effect. (3) Finally, we introduce an early fusion deep layer that combines image-based and LiDAR-derived features. In a benchmark study carried out using the Follo 2014 LiDAR data and the NIBIO AR5 land resources dataset, we compare our proposals to other deep learning architectures. A quantitative comparison shows that our best proposal provides more than 5% relative improvement in terms of mean intersection-over-union over the atrous network, providing a basis for a more frequent and improved use of LiDAR data for automatic land cover segmentation.
Vitenskapelig – Microsatellites as a tool for Identifying successful pollinators of the pear cultivar ‘Ingeborg’ in Ullensvang, Norway
Mekjell Meland, Mirsad Kurtovic, Belma Kalamujic, ...
Due to their Mendelian inheritance, microsatellites or SSRs (simple sequence repeats) can readily be used for parentage analyses of pear seedlings, thus revealing the female and male parents of the plant. However, in cases where obtained pear seeds display low viability, conducting a parentage analyses on the pear seeds themselves could be used in order to identify the male parent (successful pollinator). In this study, batches of seeds were extracted from fruits of the triploid ‘Ingeborg’ pear (‘Conference’ × ‘Bonne Louise’), the main commercial pear cultivar in Norway. Mature pears were collected from eight commercial pear orchards located in Ullensvang, at 60° North and seeds were collected. Genomic DNA was subsequently isolated from the obtained seed batches and genotyped using 12 microsatellite markers. The same markers were also used for the genetic characterization of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards (‘Clara Frijs’, ‘Herzogine Elsa’, ‘Anna’, ‘Colorée de Juillet’ and ‘Belle lucrative’). The obtained SSR profiles were used in paternity analyses, as well as for gene assignment analyses. Both approaches identified pear ‘Clara Frijs’ to be the most successful pollinator in most of the sampled orchards. Subsequent S allele genotyping of ‘Ingeborg’ and five pear genotypes used as pollinators in the sampled orchards revealed that the preferential pollination by individual genotypes was not caused by gametophytic incompatibility or semi-compatibility.
Vitenskapelig – Potential impacts of climate change on soil properties
Györgyi Gelybò, E. Toth, Csilla Farkas, ...
Climate change is expected to have a vigorous impact on soils and ecosystems due to elevated temperature and changes in precipitation (amount and frequency), thereby altering biogeochemical and hydrological cycles. Several phenomena associated with climate change and anthropogenic activity affect soils indirectly via ecosystem functioning (such as higher atmospheric CO2 concentration and N deposition). Continuous interactions between climate and soils determine the transformation and transport processes. Long-term gradual changes in abiotic environmental factors alter naturally occurring soil forming processes by modifying the soil water regime, mineral composition evolution, and the rate of organic matter formation and degradation. The resulting physical and chemical soil properties play a fundamental role in the productivity and environmental quality of cultivated land, so it is crucial to evaluate the potential outcomes of climate change and soil interactions. This paper attempts to review the underlying long-term processes influenced by different aspects of climate change. When considering major soil forming factors (climate, parent material, living organisms, topography), especially climate, we put special attention to soil physical properties (soil structure and texture, and consequential changes in soil hydrothermal regime), soil chemical properties (e.g. cation exchange capacity, soil organic matter content as influenced by changes in environmental conditions) and soil degradation as a result of longterm soil physicochemical transformations. The temperate region, specifically the Carpathian Basin as a heterogeneous territory consisting of different climatic and soil zones from continental to mountainous, is used as an example to present potential changes and to assess the effect of climate change on soils. The altered physicochemical and biological properties of soils require accentuated scientific attention, particularly with respect to significant feedback processes to climate and soil services such as food security.
Vitenskapelig – Selection of the best pollinizer of ‘Celina’ pear
Milica Fotiric Aksic, Radoslav Cerovic, David Slavkovic, ...
The Norwegian newly bred pear cultivar, Celina/QTee®, which was launched in 2010, has been released from the Norwegian breeding program that was initiated in 1983. It was derived from the combination ‘Colorée de Juillet’ × ‘Williams’. In Norway the flowering is medium to late and it ripens in the beginning of September. It has large attractive fruits with a red blush. It has a good fruit quality, storability and shelf life. Cross pollination is necessary in order to have high yields of this diploid cultivar. Pollination of ‘Celina’ with pollen of four donors (‘Conference’, ‘Kristina’, ‘Anna’ and ‘Fritjof’), together with open- and self-pollination were studied in this experiment during the 2016 season in Norway. The dynamics of the pollen tube growth (third, sixth and ninth day after anthesis) in style (upper, middle and lower third) and parts of the ovary in all crossing combination, were observed by fluorescent microscopy. Besides giving the best results regarding the average number of pollen tubes in different parts of pistils and the dynamics of pollen tube growth, ‘Conference’ was the only one of which the pollen tubes didn’t show any incompatible signs while growing through the transmitting tissue of the ‘Celina’ style. According to those preliminary results, ‘Conference’ was the best pollenizer, followed by ‘Kristina’. The study has to be repeated for another season.
Vitenskapelig – Tverrfaglig forskningsstøtte - et FagSosioTeknisk grenseobjekt
Nini Ebeltoft, Pål Magnus Lykkja, Atle Wehn Hegnes
It is widely acknowledged that interdisciplinary research is required for adequately addressing global challenges. This article explores what interdisciplinary research implies for research libraries assisting such work, and for researchers receiving suppo rt. The main research question is: In what manner is interdisciplinary research support shaped and constructed as a result of contact and collaboration between researchers and the research library? Along with document studies, 15 semi - structured interviews have been conducted involving academic staff at the University of Oslo (UiO) and librarians at the UiO research library. Theoretical insight from the fields of Library and Information Science and Science and Technology Studies are combined using Boundary Objects (BO) as an analytical concept. In analysing empirical data, two dual - level competencies and library practices are identified: those that are technical and librarian, and those that are academically - professional and socio - emotional. In the junctions between these, interdisciplinary research support appears as a boundary object characterized as SubjectSocioTechnical. Collaboration and support for interdisciplinary research call for a complex of competencies, primarily because various support practices must be tailored to fit researchers’ disciplines and needs.
Vitenskapelig – A novel non-segmented double-stranded RNA virus from an Arctic isolate of Pythium polare
Shinsaku Sasai, Keisuke Tamura, Motoaki Tojo, ...
We investigated virus infection in the oomycete Pythium polare from the Arctic. From 39 isolates investigated, 14 contained virus-like double-stranded RNA (dsRNA). Next generation sequencing revealed that the P. polare isolate OPU1176 contained three different virus-like sequences. We determined the full-length genome sequence of one of them. The 5397 nt-length genome had two overlapped open reading frames (ORFs) consistent with a toti and toti-like viruses, that we named Pythium polare RNA virus 1 (PpRV1). The ORF2 encoded an RNAdependent RNA polymerase (RdRp). The shifty heptamer motif and RNA pseudoknot were predicted near the stop codon of ORF1, implying that the RdRp could be translated as a fusion protein with the ORF1 protein. Phylogenetic analysis with deduced RdRp amino acid sequences indicated that oomycete virus PpRV1 was closely related to the unclassified arthropod toti-like viruses. The comparison of PpRV1-free and -infected lines suggested that PpRV1 infected in a symptomless manner.
Vitenskapelig – CRISPR versus GMOs: Public acceptance and valuation
Aaron M. Shew, L. Lanier Nalley, Heather A. Snell, ...
CRISPR gene-editing has major implications for agriculture and food security. However, no studies have evaluated the public acceptance and valuation of CRISPR-produced food. As such, we conducted a multi-country assessment of consumers’ willingness-to-consume (WTC) and willingness-to-pay (WTP) for CRISPR-produced food compared to conventional and genetically modified (GM) foods, respectively. In the USA, Canada, Belgium, France, and Australia, 56, 47, 46, 30, and 51% of respondents, respectively, indicated they would consume both GM and CRISPR food. We also found that biotechnology familiarity and perceptions of safety were the primary drivers for WTC CRISPR and GM food. Moreover, respondents valued CRISPR and GM food similarly – substantially less than conventional food – which could be detrimental for meeting future food demand.
Vitenskapelig – High tolerance of a high-arctic willow and graminoid to simulated ice encasement
Jarle W. Bjerke, Ellen Elverland, Laura Jaakola, ...
Climate change-induced snow thaw and subsequent accumulation of ice on the ground is a potential, major threat to snow-dominated ecosystems. While impacts of ground-ice on arctic wildlife are well explored, the impacts on tundra vegetation is far from understood. We therefore tested the vulnerability of two high-arctic plants, the prostrate shrub Salix polaris and the graminoid Luzula confusa, to ice encasement for 60 days under full environmental control. Both species were tolerant, showing only minor negative responses to the treatment. Subsequent exposure to simulated late spring frost increased the amount of damaged tissue, particularly in S. polaris, compared to the pre-frost situation. Wilting shoot tips of S. polaris increased nearly tenfold, while the proportion of wilted leaves of L. confusa increased by 15%. During recovery, damaged plants of S. polaris responded by extensive compensatory growth of new leaves that were much smaller than leaves of non-damaged shoots. The results suggest that S. polaris and L. confusa are rather tolerant to arctic winter-spring climate change, and this may be part of the reason for their wide distribution range and abundance in the Arctic.
Vitenskapelig – SWAT model uncertainties and cumulative probability for decreased phosphorus loading by agricultural Best Management Practices
Alexander Engebretsen, Rolf David Vogt, Marianne Bechmann
Effects of mitigation measures in agriculture on abating eutrophication are difficult to evaluate by assessments of catchment monitoring data. Estimates of improved water quality by specific agricultural Best Management Practices (BMPs) are therefore often dependent on simulation modeling. A main objective was thus to assess the probable reductions in total phosphorus (TP) loading achieved by implemented agricultural mitigation measures. The case-study site was a catchment in southeastern Norway. Simulation modeling was conducted by use of The Soil and Water Assessment Tool (SWAT). The aim of this present study was to understand the model uncertainty associated both with calibration/validation (baseline) and TP loading scenarios based on BMP. The modeled decrease in TP loading by the set of implemented BMPs was assessed by comparing simulated baseline output with output where the set of abatement actions were removed. The model was set up for the years 2006–2010 and calibrated against observed monitoring data, including daily discharge, sediment- and TP fluxes. Model simulations were performed including and excluding the implemented set of mitigation measures. The simulated set of mitigation measures include decrease in amount of phosphorus fertilization, establishment of vegetated buffer strips along streams and constructed wetlands in the water courses, no autumn tilling and removal of point TP sources from scattered dwellings. Model calibration and uncertainty estimation are performed using an algorithm for Sequential Uncertainty Fitting (SUFI2; ver. 2). Probabilistic risk for given magnitudes of increased TP loading if existing BMPs were not implemented was assessed. Using this novel approach it was possible to state, with a 80th percentile confidence level, that the average annual TP loading would have been about 26% higher if no mitigation measures were implemented in the catchment. This was possible to assess even though the difference between baseline and BMP scenario was not significant.
Vitenskapelig – Water up-take in fuel pellets studied by Dynamic Vapour Sorption (DVS) analysis and its potential role in self-heating during storage
Calle Nilsson, Henrik Ramebäck, Callum Aidan Stephen Hill, ...
The self-heating of wood fuel pellets is a well-recognised problem causing fire incidents in the storage of the pellets as well as severe intoxication of workers by elevated carbon monoxide and carbon dioxide levels and oxygen depletion. Possible factors contributing to the self-heating are considered to be autoxidation and microbiological activity, while the role and contribution to the temperature rise caused by the heat of condensation from water vapour condensing during fast changes in the relative air humidity is less investigated. Using Dynamic Vapour Sorption, the water uptake was measured at 25 °C when increasing the RH from 40 to 80% using 35 fuel pellet samples covering a broad variation in pellet raw materials and process equipment found in Europe (both pilot and industrial scale). The equilibrium total water uptake and speed of the uptake were determined. Total water uptake was 4.56% (range 3.69–6.86%) with no systematic difference found related to the scale of production (industry as compared to pilot plant). In addition, the variations within larger groups of raw material (pine, spruce and pine/spruce mixtures) were relatively small, and the mean water uptake did not differ significantly between these groups. An estimation of the overall potential heat release (when raising the RH% from 40 to 80%) made from the experimental results, taking the early fast water uptake process into consideration (2 h counting for half the total uptake), showed that a heat release of 47 kJ/kg of pellets (range 12–63 kJ/kg) and a potential temperature increase of 45 °C is possible. This estimation clearly demonstrates that the heat of condensation released during water condensation in a pellets silo or in a pellets pile should be expected to be a major contributing factor to initiating temperature rise incidents. In addition, such a temperature increase is expected to assist the initiation of, and to increase the speed of autoxidation of fatty acids and other compounds in the material that will further contribute to a temperature rise. Thus, the results in this study have the potential to improve the basis for modelling the self-heating process in pellet silos/storage and to predict the status of a certain pellet batch by presenting a broad basis for expected variation in the important parameters (specific heat capacity CP and thermal conductivity λeff) influencing the process, and thus aid in taking preventive actions like venting or shifting the pellets to another silo/pile to reduce risk for self-heating and possible fire.
Vitenskapelig – Effects of renewal time, taproot cutting, ploughing practice, false seedbed and companion crop on docks (Rumex spp.) when renewing grassland
Björn Ringselle, Therese W. Berge, Daniel Stout, ...
Docks (Rumex spp.) are a considerable problem in grassland production worldwide. We investigated how different cultural management techniques affected dock populations during grassland renewal: (I) renewal time, (II) companion crop, (III) false seedbed, (IV) taproot cutting (V), plough skimmer and (VI) ploughing depth. Three factorial split-split plot experiments were carried out in Norway in 2007–2008 (three locations), 2008–2009 (one location) and 2009 (one location). After grassland renewal, more dock plants emerged from seeds than from roots. Summer renewal resulted in more dock seed and root plants than spring renewal. Adding a spring barley companion crop to the grassland crop often reduced dock density and biomass. A false seedbed resulted in 71% fewer dock seed plants following summer renewal, but tended to increase the number of dock plants after spring renewal. In some instances, taproot cutting resulted in less dock biomass, but the effect was weak and inconsistent, and if ploughing was shallow (16 cm) or omitted, it instead increased dock root plant emergence. Fewer root plants emerged after deep ploughing (24 cm) compared to shallow ploughing, and a plough skimmer tended to reduce the number further. We conclude that a competitive companion crop can assist in controlling both dock seed and root plants, but it is more important that the renewal time is favourable to the main crop. Taproot cutting in conjunction with ploughing is not an effective way to reduce dock root plants, but ploughing is more effective if it is deep and a skimmer is used.
Vitenskapelig – In vitro pepsin digestibility and amino acid composition in soluble and residual fractions of hydrolyzed chicken feathers
Steffen Adler, Rasa Slizyte, Kaisu Honkapää, ...
Beta-keratin in poultry feathers is a structural protein that is resistant to degradation due to disulfide and hydrogen bonds. Feather meal can be a valuable feed compound if the digestibility can be increased. The objective of the present study was to analyze the effects of chemical, enzymatic, and pressure-thermic treatments for chicken feathers on solubility, in vitro protein digestibility (IVPD), and amino acid composition of solubilized and residual fractions. Two experiments were conducted. In experiment 1, models for solubility and IVPD were developed including the above factors applying a central composite face-centered design. Addition of sodium hydroxide (NaOH) and sodium sulfite (Na2SO3), and autoclaving time affected solubility and IVPD of the feather hydrolysates, but not addition of keratinolytic enzyme. In experiment 2, 7 combinations of the hydrolysis factors NaOH, Na2SO3, and autoclaving time with a predicted IVPD of 900 g/kg of DM, calculated for the sum of solubilized and residual feather fractions, were included to measure effects on IVPD and amino acid composition in each fraction. The IVPD values were higher for solubilized than residual fractions when treated with NaOH and autoclaving, but no differences were found when treated with Na2SO3 and autoclaving. Losses of cystine were substantial for all treatments, but lower for Na2SO3 than for NaOH. Furthermore, use of lower Na2SO3 concentration and longer autoclaving time reduced losses of cystine. Compared with NaOH treatments, Na2SO3 gave lower losses of threonine, arginine, serine, and tyrosine. With reference to the ideal protein profile for Atlantic salmon (Salmo salar L.), the treatments with 60 or 90 min autoclaving and 0.36 or 0.21% Na2SO3 had the highest chemical scores. The scores were generally higher for amino acids in residual than solubilized fractions, but with 90 min autoclaving and 0.21% Na2SO3 differences were small. In conclusion, hydrolysis of chicken feathers with low concentrations of Na2SO3 combined with autoclaving results in feather meal with high nutritional value for Atlantic salmon; separation of solubilized and residual fractions is not necessary.
Vitenskapelig – Automated image analysis tool to measure microbial growth on solid cultures
Francisco Javier Ancin Murguzur, Aitor Barbero-Lopez, Sari Kontunen-Soppela, ...
Microbial growth on culture media is a commonplace technique to estimate the growth rate and virulence ofmicrobes, assess inhibitory effects of compounds and estimate potential damages of plant pathogens in agri-culture. Growth area measurement of solid cultures is still commonly performed as a manual process that re-quires skilled technicians and substantial time, thus warranting an automated system to reduce the workload andincrease measurement efficiency. A machine learning approach (Support Vector Machines) was developed tofully automate the area measurement process. We developed a functional model that processes images andreturns the microbial area coverage considerably faster than a manual measurement method, with minimal userinput and highly comparable results (R2= 0.88, kappa = 0.88) applicable over large datasets.
Vitenskapelig – Metabolomics: A High-throughput Screen for Biochemical and Bioactivity Diversity in Plants and Crops
Alexandre Foito, Derek Stewart
Plants and crops contain a staggering diversity of compounds, many of which have pharmacological activity towards a variety of diseases. These properties have been exploited by traditional and modern medicine providing important sources of healthcare to this day. The contribution of natural products (such as plant-derived) to the modern pharmacopeia is indeed significant; however, the process of identifying novel bioactive compounds from biological sources has been a central challenge in the discovery of natural products. The resolution of these challenges relied extensively on the use of hyphenated Mass Spectrometry (MS) and Nuclear Magnetic Resonance (NMR)-based analytical technologies for the structural elucidation and annotation of novel compounds. Technical developments in instrumentation and data processing have fostered the development of the field of metabolomics which provides a wealth of tools with the huge potential for application in the process of drug/bioactive discovery from plant tissues. This manuscript provides an overview of the metabolomics toolbox available for the discovery of novel bioactive compounds and the integration of these tools in the bioprospection and drug discovery workflows.
Vitenskapelig – Knockdown of a mucin-like gene in Meloidogyne incognita (Nematoda) decreases attachment of endospores of Pasteuria penetrans to the infective juveniles and reduces nematode fecundity
Victor Phani, Tagginahalli N. Shivakumara, Keith Davies, ...
Mucins are highly glycosylated polypeptides involved in many host–parasite interactions, but their function in plant-parasitic nematodes is still unknown. In this study, a mucin-like gene was cloned from Meloidogyne incognita (Mi-muc-1, 1125 bp) and characterized. The protein was found to be rich in serine and threonine with numerous O-glycosylation sites in the sequence. Quantitative real-time polymerase chain reaction (qRT-PCR) showed the highest expression in the adult female and in situhybridization revealed the localization of Mi-muc-1 mRNA ex-pression in the tail area in the region of the phasmid. Knockdown of Mi-muc-1 revealed a dual role: (1) immunologically, there was a significant decrease in attachment of Pasteuria penetrans en-dospores and a reduction in binding assays with human red blood cells (RBCs), suggesting that Mi-MUC-1 is a glycoprotein present on the surface coat of infective second-stage juveniles (J2s) and is involved in cellular adhesion to the cuticle of infective J2s; pretreatment of J2s with different carbohydrates indicated that the RBCs bind to J2 cuticle receptors different from those involved in the interaction of Pasteuria endospores with Mi-MUC-1; (2) the long-term effect of RNA interference (RNAi)-mediated knockdown of Mi-muc-1 led to a significant reduction in nematode fecundity, suggesting a possible function for this mucin as a mediator in the interaction between the nematode and the host plant.
Vitenskapelig – Comparison of regular atmospheric storage versus modified atmospheric packaging on postharvest quality of organically grown lowbush and half-highbush blueberries
Angela Koort, Ulvi Moor, Priit Poldma, ...
The aim of the study was to determine the effect of modified atmosphere (MA) packages on the external quality of organically grown lowbush blueberry and half-highbush blueberry (’Northblue’) and the nutritional value of the fruits. Fruits were divided into plastic punnets and stored as follows: regular atmosphere (RA), punnets without packing; punnets sealed in a low-density polyethylene (LDPE, Estiko) bag; punnets sealed in an Xtend® blueberry bag (Stepac). Fruits were stored at 3 ± 1 ◦C. Compared to RA conditions, the Xtend® package prolonged the postharvest life for 15 days for lowbush and 9 days for half-highbush blueberries. Fruit dry matter (DM) and titratable acidity (TA) were higher in the Xtend® package. Fruit SSC decreased in the LDPE packages and increased in the Xtend® packages during storage. Based on the decreased soluble solids content (SSC) and titratable acidity (TA) ratio (SSC:TA) values during storage, it can be concluded that the taste of the fruits became sourer in all packages. Anthocyanin biosynthesis of lowbush blueberries was suppressed in MA, but this effect was not noticed for ‘Northblue’. Regarding fruit firmness, shrivelling, and decay, there were significant differences between the MA packages, but the genetic differences were more important: half-highbush blueberry fruits were firmer and less shrivelled.
Vitenskapelig – Pathogenicity of Neonectria fuckeliana on Norway Spruce Clones in Sweden and Potential Management Strategies
Martin Pettersson, Venche Talgø, John Frampton, ...
The fungus Neonectria fuckeliana has become an increasing problem on Norway spruce (Picea abies) in the Nordic countries during recent years. Canker wounds caused by the pathogen reduce timber quality and top-dieback is a problem for the Christmas tree industry. In this study, four inoculation trials were conducted to examine the ability of N. fuckeliana to cause disease on young Norway spruce plants and determine how different wound types would affect the occurrence and severity of the disease. Symptom development after 8–11 months was mainly mild and lesion lengths under bark were generally minor. However, N. fuckeliana could still be reisolated and/or molecularly detected. Slow disease development is in line with older studies describing N. fuckeliana as a weak pathogen. However, the results do not explain the serious increased damage by N. fuckeliana registered in Nordic forests and Christmas tree plantations. Potential management implications, such as shearing Christmas trees during periods of low inoculum pressure, cleaning secateurs between trees, and removal and burning of diseased branches and trees to avoid inoculum transfer and to keep disease pressure low, are based on experiments presented here and experiences with related pathogens.
Vitenskapelig – Presence of Phytophthora species in Swedish Christmas tree plantations
Martin Pettersson, John Frampton, Jonas Rönnberg, ...
Phytophthora cryptogea, P. gonapodyides, P. lacustris, P. megasperma, P. plurivora, P. taxon paludosa and an unknown Phytophthora species were isolated from waterways and soil samples in Christmas tree fields in southern Sweden. In addition, P. megasperma was isolated from a diseased Norway spruce (Picea abies) plant from one of the fields in Svalöv. Inoculation tests were sequentially carried out with one isolate from each of the three species P. cryptogea, P. megasperma, and P. plurivora, all known pathogens on conifers. The same three isolates were used to study a few morphological features to confirm the identification, and temperature-growth relationships were carried out to see how well the organisms fit into Swedish climatic conditions. Seedlings of Norway spruce and Nordmann fir (Abies nordmanniana) were inoculated in the roots and the stems. None of the isolates caused extensive root rot under the experimental conditions, but all three species could be re-isolated from both Norway spruce and Nordmann fir. Phytophthora root rot is currently of minor concern for Christmas tree growers in Sweden. However, the Phytophthora isolations from soil and water indicate the presence of this damaging agent, which may lead to future problems.
Vitenskapelig – Climate-induced changes in continental-scale soil macroporosity may intensify water cycle
Daniel R. Hirmas, Daniel Gimenez, Attila Nemes, ...
Soil macroporosity affects field-scale water-cycle processes, such as infiltration, nutrient transport and runoff1,2, that are important for the development of successful global strategies that address challenges of food security, water scarcity, human health and loss of biodiversity3. Macropores—large pores that freely drain water under the influence of gravity—often represent less than 1 per cent of the soil volume, but can contribute more than 70 per cent of the total soil water infiltration4, which greatly magnifies their influence on the regional and global water cycle. Although climate influences the development of macropores through soil-forming processes, the extent and rate of such development and its effect on the water cycle are currently unknown. Here we show that drier climates induce the formation of greater soil macroporosity than do more humid ones, and that such climate-induced changes occur over shorter timescales than have previously been considered—probably years to decades. Furthermore, we find that changes in the effective porosity, a proxy for macroporosity, predicted from mean annual precipitation at the end of the century would result in changes in saturated soil hydraulic conductivity ranging from −55 to 34 per cent for five physiographic regions in the USA. Our results indicate that soil macroporosity may be altered rapidly in response to climate change and that associated continental-scale changes in soil hydraulic properties may set up unexplored feedbacks between climate and the land surface and thus intensify the water cycle.
Vitenskapelig – Quantiﬁcation of dissolved organic carbon (DOC) storage in lakes and reservoirs of mainland China
Kaishan Song, Zhidan Wen, Yingxing Shang, ...
As a major fraction of carbon in inland waters, dissolved organic carbon (DOC) plays a crucial role incarbon cycling on a global scale. However, the quantity of DOC stored in lakes and reservoirs was notclear to date. In an attempt to examine the factors that determine the DOC storage in lakes and reservoirsacross China, we assembled a large database (measured 367 lakes, and meta-analyzed 102 lakes from ﬁvelimnetic regions; measured 144 reservoirs, and meta-analyzed 272 reservoirs from 31 provincial units) ofDOC concentrations and water storages for lakes and reservoirs that are used to determine DOC storagein static inland waters. We found that DOC concentrations in saline waters (Mean/median ± S.D: 50.5/30.0 ± 55.97 mg/L) are much higher than those in fresh waters (8.1/5.9 ± 6.8 mg/L), while lake DOCconcentrations (25.9/11.5 ± 42.04 mg/L) are much higher than those in reservoirs (5.0/3.8 ± 4.5 mg/L). Interms of lake water volume and DOC storage, the Tibet-Qinghai lake region has the largest water volume(552.8 km3), 92% of which is saline waters, thus the largest DOC (13.39 Tg) is stored in these alpine lakeregion; followed by the Mengxin lake region, having a water volume of 99.4 km3in which 1.75 Tg DOCwas stored. Compared to Mengxin lake region, almost the same amount of water was stored in East Chinalake region (91.9 km3), however, much less DOC was stored in this region (0.43 Tg) due to the lower DOCconcentration (Ave: 3.45 ± 2.68 mg/L). According to our investigation, Yungui and Northeast lake regionshad water storages of 32.14 km3and 19.44 km3respectively, but relatively less DOC was stored in Yungui(0.13 Tg) than in Northeast lake region (0.19 Tg). Due to low DOC concentration in reservoirs, especiallythese large reservoirs having lower DOC concentration (V > 1.0 km3: 2.31 ± 1.48 mg/L), only 1.54 Tg wasstored in a 485.1 km3volume of water contained in reservoirs across the entire country.
Vitenskapelig – A Wind Tunnel for Odor Mediated Insect Behavioural Assays
Geir Kjølberg Knudsen, Marco Tasin, Anders Aak, ...
Olfaction is the most important sensory mechanism by which many insects interact with their environment and a wind tunnel is an excellent tool to study insect chemical ecology. Insects can locate point sources in a three-dimensional environment through the sensory interaction and sophisticated behavior. The quantification of this behavior is a key element in the development of new tools for pest control and decision support. A wind tunnel with a suitable flight section with laminar air flow, visual cues for in-flight feedback and a variety of options for the application of odors can be used to measure complex behaviour which subsequently may allow the identification of attractive or repellent odors, insect flight characteristics, visual-odor interactions and interactions between attractants and odors lingering as background odors in the environment. A wind tunnel holds the advantage of studying the odor mediated behavioural repertoire of an insect in a laboratory setting. Behavioural measures in a controlled setting provide the link between the insect physiology and field application. A wind tunnel must be a flexible tool and should easily support the changes to setup and hardware to fit different research questions. The major disadvantage to the wind tunnel setup described here, is the clean odor background which necessitates special attention when developing a synthetic volatile blend for field application.
Vitenskapelig – Adaptability of hull-less barley varieties to different cropping systems and climatic conditions
Ievina Sturite, Arta Kronberga, Vija Strazdina, ...
Multilocation testing remains the main tool for understanding varietal responses to the environment. Here, Latvian and Norwegian hull-less and hulled barley varieties were tested in field experiments in Latvia and Norway in order to assess the varieties adaptability across environments (sites). Two Latvian (cv Irbe and cv Kornelija) and one Norwegian hull-less barley variety (cv Pihl) were tested along with one Latvian (cv Rubiola) and one Norwegian hulled barley variety (cv Tyra) under conventional and organic management systems. The grain yield, together with physical and chemical grain parameters were compared, and variety yield and protein stability detemined. Overall, grain yield of hull-less barley varieties was significantly lower than for hulled barley varieties regardless of climatic conditions and management system. However, in the organic farming systems this difference between barley types was less pronounced. The hull-less barley varieties cv Pihl and cv Irbe, along with both hulled varieties, had good yield stability across environments and were well adapted to both cropping systems. Hull-less barley varieties tended to contain more protein and β -glucans than hulled barley varieties. Despite being bred for local conditions in Norway and Latvia, our study shows that all the varieties used may be successfully transferred across countries.
Vitenskapelig – Effects of Climate Change on Grassland Biodiversity and Productivity: The Need for a Diversity of Models
Marcel van Oijen, Gianni Bellocchi, Mats Höglind
There is increasing evidence that the impact of climate change on the productivity of grasslands will at least partly depend on their biodiversity. A high level of biodiversity may confer stability to grassland ecosystems against environmental change, but there are also direct effects of biodiversity on the quantity and quality of grassland productivity. To explain the manifold interactions, and to predict future climatic responses, models may be used. However, models designed for studying the interaction between biodiversity and productivity tend to be structurally different from models for studying the effects of climatic impacts. Here we review the literature on the impacts of climate change on biodiversity and productivity of grasslands. We first discuss the availability of data for model development. Then we analyse strengths and weaknesses of three types of model: ecological, process-based and integrated. We discuss the merits of this model diversity and the scope for merging different model types.
Vitenskapelig – Bark Beetle-Associated Blue-Stain Fungi Increase Antioxidant Enzyme Activities and Monoterpene Concentrations in Pinus yunnanensis
Yue Pan, Tao Zhao, Paal Krokene, ...
Yunnan pine is the most important tree species in SW China in both economical and ecological terms, but it is often killed by pine shoot beetles (Tomicus spp.). Tomicus beetles are secondary pests in temperate regions and the aggressiveness of the beetles in SW China is considered to be due to the warm subtropical climates as well as the beetles’ virulent fungal associates. Here, we assessed the virulence of three blue-stain fungi (Leptographium wushanense, L. sinense and Ophiostoma canum) associated with pine shoot beetles to Yunnan pine (Pinus yunnanensis) in SW China. Following fungal inoculation, we measured necrotic lesion lengths, antioxidant enzyme activities and monoterpene concentrations in the stem phloem of Yunnan pine. Leptographium wushanense induced twice as long lesions as L. sinense and O. canum, and all three fungi induced significantly longer lesions than sterile agar control inoculations. The activity of three tested antioxidant enzymes (peroxidase, polyphenol oxidase, and superoxide dismutase) increased after both fungal inoculation and control inoculation. However, L. wushanense and L. sinense generally caused a greater increase in enzyme activities than O. canum and the control treatment. Fungal inoculation induced stronger increases in six major monoterpenes than the control treatment, but the difference was significant only for some fungus-monoterpene combinations. Overall, our results show that L. wushanense and L. sinense elicit stronger defense responses and thus are more virulent to Yunnan pine than O. canum. The two Leptographium species may thus contribute to the aggressiveness of their beetle vectors and could damage Yunnan pine across SW China if they spread from the restricted geographical area they have been found in so far.
Vitenskapelig – Polyesterification of wood using sorbitol and citric acid under aqueous conditions
Erik Larnøy, A. Karaca, Lone Ross Gobakken, ...
The aim of this research is to determine if the polyesterification of sorbitol and citric acid in wood has a future potential as a wood modification process. Pine wood was impregnated with an aqueous solution containing citric acid and sorbitol and was thereafter cured at 103 or 140°C for 18 hours. The dimensional stability and leaching resistance were studied for both modification temperatures. The leachates from the modified wood samples were analysed by HPLC and the susceptibility to decay and staining fungi were studied. Impregnated samples cured at 140°C showed a permanent (leach-resistant) increased dimensional change, but samples treated at 103°C were not stable to leaching. Treated samples cured at 103 and 140°C showed significant resistance to white-rot (Trametes versicolor) and brown-rot decay (Postia placenta) after a leaching procedure. Furthermore, samples cured at 103 and 140°C (leached and unleached) were significantly less susceptible to blue-stain fungi than the untreated controls.
Vitenskapelig – Neighbourhood convenience stores and childhood weight outcomes: an instrumental variable approach
Di Zeng, Michael R. Thomsen, Rodolfo M. Jr. Nayga, ...
The association between the commercial food environment and childhood obesity is increasingly assessed in the literature, but little is known about the role of convenience stores, an important food retail format worldwide. This study helps bridge the gap using individual-level data containing measured body mass index (BMI) for public schoolchildren and geo-coded residence and store locations in Arkansas, United States. The distance from residence to the nearest highway is employed to instrument neighbourhood convenience store exposure, while controlling for possible confounding effects of other food stores. We find that exposure to at least one convenience store exposure is associated with a BMI z-score increase of 0.162 SD, and exposure to each additional convenience store is associated with a BMI increase of 0.071 SD. There is no evidence for a larger association among children from low-income families or those with limited access to healthy foods.
Vitenskapelig – Growth pattern of Juncus effusus and Juncus conglomeratus in response to cutting frequency
Wiktoria Anna Kaczmarek-Derda, Liv Østrem, Merete Myromslien, ...
Increasing abundance of Juncus effusus (soft rush) and Juncus conglomeratus (compact rush) in pastures and meadows in western Norway has caused reductions in forage yield and quality in recent decades. Understanding plant development and regrowth following cutting is essential in devising cost-effective means to control rushes. In a ﬁeld experiment in western Norway, we investigated development of above- and below-ground fractions of rush from seedlings to three-year-old plants, including the impact on vigour of disturbing growth by different cutting frequencies during the period 2009–2012. Each year, the plants were exposed to one or two annual cuts or left untreated and ﬁve destructive samplings were performed from March to early December. Juncus effusus showed signiﬁcantly more vigorous growth than Juncus conglomeratus in the last two years of the study period. The above-ground:below-ground biomass ratio of both species increased mainly in spring and early summer and was reduced in late summer and autumn. Removal of aerial shoots also reduced the below-ground fraction of both species. One annual cut in July effectively reduced biomass production in both species by 30–82%, which was only a slightly smaller reduction than with two annual cuts, in June and August. Mechanical control measures such as cutting can thus effectively reduce rush vigour when performed late in the growing season.
Vitenskapelig – Links between profitability, nitrogen surplus, greenhouse gas emissions, and energy intensity on organic and conventional dairy farms
Ola Flaten, Matthias Koesling, Sissel Hansen, ...
This study examines the relationships between profitability, nitrogen (N) surplus, greenhouse gas emissions (GHG), and energy intensity and factors influencing these relationships in dairy farming. In-depth data from 10 conventional and 8 organic dairy farms in Western Norway were analyzed. Organic farms had lower N surplus per hectare (local, onfarm) and per unit output (global, cradle-to-farm-gate), and lower estimated GHG emissions and energy intensity per unit output, whereas labor input and farm profits did not differ. Higher profitability tended to be associated with improved performance of the environmental indicators examined. Intensification through increased use of concentrates tended to improve profit and reduce N surplus, GHG emissions, and energy intensity per unit output within each farming system while N surplus per hectare could be negatively affected. To ensure a balanced representation of the environmental consequences of both organic and conventional farming systems,our results give support to extensive examination of both area and product-based environmental performance indicators.
Vitenskapelig – Estimating the Permeability of Naturally Structured Soil From Percolation Theory and Pore Space Characteristics Imaged by X-Ray
John Koestel, Annette Dathe, Todd H. Skaggs, ...
The saturated hydraulic conductivity of soil, Ks, is a critical parameter in hydrological models that remains notoriously difficult to predict. In this study, we test the capability of a model based on percolation theory and critical path analysis to estimate Ks measured on 95 undisturbed soil cores collected from contrasting soil types. One parameter (the pore geometry factor) was derived by model fitting, while the remaining two parameters (the critical pore diameter, dc, and the effective porosity) were derived from X‐ray computed tomography measurements. The model gave a highly significant fit to the Ks measurements (p < 0.0001) although only ~47% of the variation was explained and the fitted pore geometry factor was approximately 1 to 2 orders of magnitude larger than various theoretical values obtained for idealized porous media and pore network models. Apart from assumptions in the model that might not hold in reality, this could also be attributed to experimental error induced by, for example, air entrapment and changes in the soil pore structure occurring during sample presaturation and the measurement of Ks. Variation in the critical pore diameter, dc, was the dominant source of variation in Ks, which suggests that dc is a suitable length scale for predicting soil permeability. Thus, from the point of view of pedotransfer functions, it could be worthwhile to direct future research toward exploring the correlations of dc with basic soil properties and site attributes.
Vitenskapelig – Towards a population approach for evaluating grassland restoration—a systematic review
Mélanie Harzé, Arnaud Monty, Sylvain Boisson, ...
Persistence of restored populations depends on growth, reproduction, dispersal, local adaptation, and a suitable landscape pattern to foster metapopulation dynamics. Although the negative effects of habitat fragmentation on plant population dynamics are well understood, particularly in grasslands, the population traits that control grassland restoration are less known. We reviewed the use of population traits for evaluating grassland restoration success based on 141 publications (1986–2015). The results demonstrated that population demography was relatively well‐assessed but detailed studies providing information on key stages of the life cycle were lacking despite their importance in determining population viability. Vegetative and generative performances have been thoroughly investigated, notably the components of plant fitness, such as reproductive output, while genetic and spatial population structures were largely ignored. More work on the population effects of ecological restoration would be welcomed, particularly with a focus on population genetics. Targeted species were principally common and dominant natives, or invasive plants while rare or threatened species were poorly considered. Evaluation of ecological restoration should be conducted at different scales of ecological complexity, but so far, communities and ecosystems are over represented, and more focus should be directed towards a population approach as population traits are essential indicators of restoration success.
Vitenskapelig – Selecting plant species and traits for phytometer experiments. The case of peatland restoration
Katharina Strobl, Claudia Schmidt, Johannes Kollmann
Phytometers are indicator transplants that provide information on site conditions based on plant survival,growth and reproduction. Since this is a relatively new approach, standards for its implementation remain to bedeﬁned, for example, during peatland restoration. Peatland restoration frequently aims at recovering char-acteristic communities, and a key attribute of successfully restored ecosystems is their capacity to sustain viablepopulations of target species. When not actively introduced, these species are expected to establish on their ownafter improving site conditions, for example by rewetting. Assessments to determine whether this goal is metrequire the long-term monitoring of species’ presence, whereas the underlying causes of these observations, i.e.site or dispersal limitation, often remain unknown. Using phytometers within ecological restoration helps ad-dressing this question. The goal of this study is to compare the responses of several species and traits to en-vironmental conditions in restored peatlands. Three target species (Drosera rotundifolia, Eriophorum vaginatum,Vaccinium oxycoccos) were planted in restored montane peatlands in central Germany, while in a greenhouseexperiment, the same species were grown on peat from the ﬁeld sites and exposed to two water levels. Severalplant traits were measured and compared with variation in light, water and soil conditions. The response tohabitat conditions was species-speciﬁc, indicating that the use of diﬀerent phytometers increases the reliabilityof monitoring. Survival and growth traits were suitable to assess a wide range of abiotic conditions, whilediﬀerences in reproductive output were more time-consuming to measure. Survival provided the most conclusiveresults for species sensitive to stressful habitat conditions. Biomass and other size metrics of the phytometers, aswell as growth and reproductive traits were partly redundant. Thus, we suggest recording survival and biomassand use non-destructive growth measurements for repeated assessments, while the choice of the most suitablesize trait should depend on the growth form. Our study stresses the potential of phytometers for monitoring therestoration outcome, while highlighting the importance of species and trait selection.
Vitenskapelig – Economic performance and efficiency determinants of crop-producing farms in Norway
Habtamu Alem, Gudbrand Lien, J. Brian Hardaker
Purpose – The purpose of this paper is to explore the economic performance of Norwegian crop farms using a stochastic frontier analysis. Design/methodology/approach – The analysis was based on a translog cost function and unbalanced farm-level panel data for 1991–2013 from 455 Norwegian farms specialized in crop production in eastern and central regions of Norway. Findings – The results of the analysis show that the mean efficiency was about 78–81 percent. Farm management practices and socioeconomic factors were shown to significantly affect the economic performance of Norwegian crop farms. Research limitations/implications – Farmers are getting different types of support from the government and the study does not account for the different effects of different kinds of subsidy on cost efficiency. Different subsidies might have different effects on farm performance. To get more informative and useful results, it would be necessary to repeat the analysis with less aggregated data on subsidy payments. Practical implications – One implication for farmers (and their advisers) is that many of them are less efficient than the estimated benchmark (best performing farms). Thus, those lagging behind the best performing farms need to look at the way they are operating and to seek out ways to save costs or increase crop production. Perhaps there are things for lagging farmers to learn from their more productive farming neighbors. For instance, those farmers not practicing crop rotation might be well advised to try that practice. Social implications – For both taxpayers and consumers, one implication is that the contributions they pay that go to subsidize farmers appear to bring some benefits in terms of more efficient production that, in turn, increase the supply of some foods so possibly making food prices more affordable. Originality/value – Unlike previous performance studies in the literature, the authors estimated farm-level economic performance accounting for the contribution of both an important farm management practice and selected socioeconomic factors. Good farm management practices, captured through crop rotation, land tenure, government support and off-farm activities were found to have made a positive and statistically significant contribution to reducing the cost of production on crop-producing farms in the Central and Eastern regions of Norway.
Vitenskapelig – Experiences with autumn fertilization in berry crops
Tomasz Leszek Woznicki, Ola M Heide, Anita Sønsteby
The effect of controlled nutrient feeding during the period of short day (SD) induction of flowering has been studied in three SD berry crops. An experimental system with standardized plant material grown with trickle fertigation in controlled environments was used. In strawberry, flowering was advanced and increased when an additional N pulse was given 1-2 weeks after commencement of a 4-week SD induction period, while the opposite resulted when the treatment was applied 2 weeks before start of SD. In blackcurrant, the highest flowering and yield were obtained when fertilization was applied shortly after the natural photoperiod had declined to the inductive length in September. While generous nutrient supply during spring and summer reduced berry soluble solids in blackcurrant, this was not observed with autumn fertilization. Autumn fertilization did not adversely affect plant winter survival or growth vigour in spring. Withdrawal of fertilization prior to, or at various stages during floral induction, did not significantly affect flowering and yield in raspberry, but marginally advanced flowering and fruit ripening.
Vitenskapelig – The use of rented farmland in an area of intensive agricultural production in Norway
Tone Stokka, Wenche Dramstad, Kerstin Potthoff
The amount of rented farmland in Norway has increased steadily since the 1950s. Concerns have been raised questioning whether farmland is treated less well by tenants compared to landowners. This study aims to investigate how farmers perceive their treatment of rented farmland, which factors impact their decisionmaking related to this and if farmers are concerned about farmland elements that are less important for productivity but mainly of interest for cultural heritage or environmental management reasons. Semi-structured interviews with a group of randomly selected farmers were carried out in an area dominated by intensive agriculture. Independent of, for example, amount of rented land or duration of the rental agreement, all farmers agreed that rented land was treated well. A strong competition for farmland in combination with farmers being dependent on renting land was the most important reason. Results from this study may be transferrable to other farming areas, at least where competition for farmland is comparable. We do suggest, however, that any further research on treatment of rented farmland in Norway should take a regional approach, since national statistics may cover significant regional differences.
Vitenskapelig – Low phosphorus availability increases shoot boron concentration in canola and potato but not in wheat
Yanliang Wang, Nicholas Clarke, Anne Falk Øgaard
A large proportion of global agricultural soils contain suboptimal available phosphorus (P) for the growth of many plant species. Boron (B) plays important roles in plant growth and development, but limited research has been conducted to study B uptake under low P availability. This study comprised a hydroponic and a mini-rhizobox experiment with canola (Brassica napus L.), potato (Solanum tuberosum L.) and wheat (Triticum aestivum L.) under P sufficient and deficient conditions. Boron concentrations, rhizosphere soil pH, and gene expression of BnBOR1 in canola were determined. Shoot B concentrations were found significantly increased (11–149%) by low P availability in potato and canola but not in wheat. Reverse transcription polymerase chain reaction (RT-PCR) indicated that BnBOR1;2a, BnBOR1;2c, and BnBOR1;3c were up-regulated after seven days of low P treatment in canola roots. Our results indicate that plant shoot B concentration was dramatically influenced by P availability, and dicots and monocots showed a contrasting B concentration response to low P availability.
Vitenskapelig – DNA from scats combined with capture–recapture modeling: a promising tool for estimating the density of red foxes — a pilot study in a boreal forest in southeast Norway
Per Wegge, Beate Banken Bakke, Morten Odden, ...
In spite of its important role as predator of small game species, estimating the density of red fox Vulpes vulpes has been hampered by the species’ highly variable ranging pattern and elusive behavior. DNA analysis from scats combined with spatially explicit capture–recapture (SECR) modeling might remedy this. In a 50-km2 coniferous forest in southeast Norway, we collected scats on logging roads in late winter. DNA was extracted, amplified, and genotyped using 11 microsatellite markers. Of 184 samples collected, 126 were genotyped successfully, of which 46 (36.5%) produced individual genetic profiles. Twenty-five of these were different individuals: 13 females and 12 males. Nine of them were identified in multiple scats; mean recapture rate among all was 1.8/animal. Applying a conventional capture–recapture model (CAPWIRE) to the genotyped samples, 36 (95% CI 26–52) different individuals were estimated to have been present in the area during the sampling period. For estimating population density, we constructed three differently sized occupancy areas based on distances between recaptures, viz. ½ and 1/1 mean maximum distance moved (MMDM) and the local convex hull home range method (LoCoH). Areas varied from 60 km2 (½MMDM) to 112 km2 (MMDM), producing density estimates of 0.60 and 0.32 foxes/km2, respectively; the 95% LoCoH range method produced an estimate of 0.44 animals/km2 . Based on SECR modeling, the density was estimated at 0.38 (95% CI 0.21–0.70) animals/km2 . Smaller confidence intervals are expected with more appropriate sampling design than used in this pilot study.
Vitenskapelig – Effects of model specification, short-run, and long-run inefficiency: an empirical analysis of stochastic frontier models
This paper examines the recent advances in stochastic frontier models and its implications for the performance of the Norwegian crop producing farms. Unlike the previous studies, we used a cost function in multiple input-output frameworks to estimate both long-run (persistent) and short-run (transient) inefficiency. The empirical analysis is based on unbalanced farm-level panel data for 1991-2013 from 455 Norwegian farms specialized in crop production with 3885 observations. We estimated seven SF panel data models grouped into four categories regarding the assumptions used to the nature of inefficiency. The estimated cost efficiency scores varied from 53 % to 95%, showing that the results are sensitive to how the inefficiency is modeled and interpreted. Keywords: cost function, short and long-run inefficiency, agriculture, panel data
Vitenskapelig – The eﬀect of freezing and thawing on water ﬂow and MCPA leaching in partially frozen soil
Roger Holten, Frederik Bøe, Marit Almvik, ...
Limited knowledge and experimental data exist on pesticide leaching through partially frozen soil. The objective of this study was to better understand the complex processes of freezing and thawing and the eﬀects these processes have on water ﬂow and pesticide transport through soil. To achieve this we conducted a soil column irrigation experiment to quantify the transport of a non-reactive tracer and the herbicide MCPA in partially frozen soil. In total 40 intact topsoil and subsoil columns from two agricultural ﬁelds with contrasting soil types (silt and loam) in South-East Norway were used in this experiment. MCPA and bromide were applied on top of all columns. Half the columns were then frozen at −3 °C while the other half of the columns were stored at +4 °C. Columns were then subjected to repeated irrigation events at a rate of 5 mm artiﬁcial rainwater for 5 h at each event. Each irrigation was followed by 14-day periods of freezing or refrigeration. Percolate was collected and analysed for MCPA and bromide. The results show that nearly 100% more MCPA leached from frozen than unfrozen topsoil columns of Hov silt and Kroer loam soils. Leaching patterns of bromide and MCPA were very similar in frozen columns with high concentrations and clear peaks early in the irrigation process, and with lower concentrations leaching at later stages. Hardly any MCPA leached from unfrozen topsoil columns (0.4–0.5% of applied amount) and concentrations were very low. Bromide showed a diﬀerent ﬂow pattern indicating a more uniform advective-dispersive transport process in the unfrozen columns with higher con- centrations leaching but without clear concentration peaks. This study documents that pesticides can be pre- ferentially transported through soil macropores at relatively high concentrations in partially frozen soil. These ﬁndings indicate, that monitoring programs should include sampling during snow melt or early spring in areas were soil frost is common as this period could imply exposure peaks in groundwater or surface water.
Vitenskapelig – Coming up short: Identifying substrate and geographic biases in fungal sequence databases
Maryia Khomich, Filipa Cox, Carrie Joy Andrew, ...
Insufﬁcient reference database coverage is a widely recognized limitation of molecular ecology ap-proaches which are reliant on database matches for assignment of function or identity. Here, we use datafrom 65 amplicon high-throughput sequencing (HTS) datasets targeting the internal transcribed spacer(ITS) region of fungal rDNA to identify substrates and geographic areas whose underrepresentation in theavailable reference databases could have meaningful impact on our ability to draw ecological conclu-sions. A total of 14 different substrates were investigated. Database representation was particularly poorfor the fungal communities found in aquatic (freshwater and marine) and soil ecosystems. Aquaticecosystems are identiﬁed as priority targets for the recovery of novel fungal lineages. A subset of the datarepresenting soil samples with global distribution were used to identify geographic locations andterrestrial biomes with poor database representation. Database coverage was especially poor in tropical,subtropical, and Antarctic latitudes, and the Amazon, Southeast Asia, Australasia, and the Indian sub-continent are identiﬁed as priority areas for improving database coverage in fungi.
Vitenskapelig – Soil ploughing for forest regeneration leads to changes in carbon decomposition - a case study with stable isotopes
Marcin Strozecki, Hanna Silvennoinen, Pawel Strzelinski, ...
It is important to quantify carbon decomposition to assess the reforestation impact on the forest floor C stocks. Estimating the loss of C stock in a short-term perspective requires measuring changes in soil respiration. This is not trivial due to the contribution of both soil microbes and vegetation to the measured CO2 flux. However, C stable isotopes can be used to partition the respiration and potentially to assess how much of the recalcitrant C stock in the forest floor is lost. Here, we measured the soil respiration at two forest sites where different regeneration methods were applied, along with an intact forest soil for reference. In so doing, we used a closed dynamic chamber for measuring respiration and the 13C composition of the emitted CO2. The chamber measurements were then supplemented with the soil organic carbon analysis and its δ13C content. The mean δ13C-CO2 estimates for the source of the CO2 were -26.4, -27.9 and -29.5‰, for the forest, unploughed and ploughed, respectively. The 13C of the soil organic carbon did, not differ significantly between sites. The higher soil respiration rate at the forest, as compared to the unploughed site, could be attributed to the autotrophic respiration by the forest floor vegetation.
Vitenskapelig – Assessing the applicability of groundwater monitoring data in the modelling of soil water retention characteristics
Wojciech Orzepowski, Adam M. Paruch, Tomasz Kowalczyk, ...
The present work focuses on an assessment of the applicability of groundwater table (GWT) measures in the modelling of soil water retention characteristics (SWRC) using artiﬁcial neural network (ANN) methods. Model development, testing, validation and veriﬁcation were performed using data collected across two decades from soil proﬁles at full-scale research objects located in Southwest Poland. A positive effect was observed between the initial GWT position data and the accuracy of soil water reserve estimation. On the other hand, no signiﬁcant effects were observed following the implementation of GWT ﬂuctuation data over the entire growing season. The ANN tests that used data of either soil water content or GWT position gave analogous results. This revealed that the easily obtained data (temperature, precipitation and GWT position) are the most accurate modelling parameters. These outcomes can be used to simplify modelling input data/parameters/variables in the practical implementation of the proposed SWRC modelling variants.
Vitenskapelig – Forest Carbon Gain and Loss in Protected Areas of Uganda: Implications to Carbon Benefits of Conservation
Belachew Gizachew, Svein Solberg, Stefano Puliti
Uganda designated 16% of its land as Protected Area (PA). The original goal was natural resources, habitat and biodiversity conservation. However, PAs also offer great potential for carbon conservation in the context of climate change mitigation. Drawing on a wall-to-wall map of forest carbon change for the entire Uganda, that was developed using two Digital Elevation Model (DEM) datasets for the period 2000–2012, we (1) quantified forest carbon gain and loss within 713 PAs and their external buffer zones, (2) tested variations in forest carbon change among management categories, and (3) evaluated the effectiveness of PAs and the prevalence of local leakage in terms of forest carbon. The net annual forest carbon gain in PAs of Uganda was 0.22 ± 1.36 t/ha, but a significant proportion (63%) of the PAs exhibited a net carbon loss. Further, carbon gain and loss varied significantly among management categories. About 37% of the PAs were “effective”, i.e., gained or at least maintained forest carbon during the period. Nevertheless, carbon losses in the external buffer zones of those effective PAs significantly contrast with carbon gains inside of the PA boundaries, providing evidence of leakage and thus, isolation. The combined carbon losses inside the boundaries of a large number of PAs, together with leakage in external buffer zones suggest that PAs, regardless of the management categories, are threatened by deforestation and forest degradation. If Uganda will have to benefit from carbon conservation from its large number of PAs through climate change mitigation mechanisms such as REDD+, there is an urgent need to look into some of the current PA management approaches, and design protection strategies that account for the surrounding landscapes and communities outside of the PAs.
Vitenskapelig – Red List updates and the robustness of sites selected for conservation of red-listed species
Ivar Gjerde, John-Arvid Grytnes, Einar Heegaard, ...
The long-term success of sites selected for species conservation depends on the persistence of target species. Red List species or threatened species lists are frequently defined as target species, but when Red Lists are updated, their species composition may change. Here we investigate the effects of Red List updates on the long-term robustness of fine-scale site selection. We used records of red-listed species (vascular plants, bryophytes, macrolichens, and polypore fungi) recorded in 1997–1998 in 1058 sample plots (50 × 50 m) from six forest landscapes in Norway, and four consecutive issues of the Norwegian Red List for species (1998, 2006, 2010, 2015). Sites were selected based on the first issue (1998) using both a scoring (“hotspot”) approach and a complementarity approach, and the ability of selected sites to include red-listed species of later issues was measured. In four boreal forests the mean proportion of red-listed species included in selected sites were reduced by18% during the study period, whereas no such effect was found in two hemiboreal forests, where increased clustering of red-listed species in sites compensated for target species changes. Changing target species adds to earlier documented challenges caused by population dynamics, and we suggest that alternatives to using occurrences of target species in site selection should be considered, and particularly at finer spatial scales.
Vitenskapelig – Long-term preservation of potato leafroll virus, potato virus S, and potato spindle tuber viroid in cryopreserved shoot tips
Jing-Wei Li, Min-Rui Wang, Hai-Yan Chen, ...
Availability of and easy access to diverse plant viruses and viroids is a prerequisite in applied and basic studies related to viruses and viroids. Long-term preservation of viruses and viroids is difficult. A protocol was described for long-term preservation of potato leafroll virus (PLRV), potato virus S (PVS), and potato spindle tuber viroid (PSTVd) in cryopreserved shoot tips of potato cv. Zihuabai. Shoot regrowth levels following cryopreservation were higher in 1.5 mm-shoot tips (58–60%) than in 0.5-mm-ones (30–38%). All shoots recovered from 0.5-mm-shoot tips were PVS- and PSTVd-preserved, but none of them were PLRVpreserved. Cryopreservation of 1.5-mm-shoot tips resulted in 35% and 100% of PLRV- and PVS- and PSTVd-preserved shoots. Studies on cell survival patterns and virus localization provided explanations to the varying PLRV-preservation frequencies produced by cryopreservation of the two sizes of shoot tips. Although micropropagation efficiencies were low after 12 weeks of subculture following cryopreservation, similar efficiencies were obtained after 16 weeks of subculture in pathogen-preserved shoots recovered from cryopreservation, compared with the diseased in vitro stock shoots (the control). Pathogen concentrations in the three pathogens-preserved shoots analyzed by qRT-PCR were similar to those in micropropagated shoots. The three pathogens cryopreserved in shoot tips were readily transmitted by grafting and mechanical inoculation to potato plants. PLRV, PVS, and PSTVd represent a diverse range of plant viruses and viroid in terms of taxonomy and infectious ability. Therefore, shoot tip cryopreservation opens a new avenue for long-term preservation of the virus and viroid.
Vitenskapelig – Imprints of management history on hemiboreal forest ecosystems in the Baltic States
Kalev Jogiste, Lee E. Frelich, Diana Laarmann, ...
In the Baltic States region, anthropogenic disturbances at different temporal and spatial scales mostly determine dynamics and development phases of forest ecosystems. We reviewed the state and condition of hemiboreal forests of the Baltic States region and analyzed species composition of recently established and permanent forest (PF). Agricultural deforestation and spontaneous or artificial conversion back to forest is a scenario leading to ecosystems designated as recent forest (RF, age up to two hundred years). Permanent forest (PF) was defined as areas with no records of agricultural activity during the last 200 yr, including mostly forests managed by traditional even-aged (clear-cut) silviculture and salvage after natural disturbances. We hypothesized that RF would have distinctive composition, with higher dominance by hardwoods (e.g., aspen and birch), compared to PF. Ordination revealed divergence in the RF stands; about half had the hypothesized composition distinct from PF, with a tight cluster of stands in the part of the ordination space with high hardwood dominance, while the remaining RF stands were scattered throughout the ordination space occupied by PF with highly variable species composition. Planting of conifers, variability in site quality, and variability in spatial proximity to PF with relatively natural ecosystem legacies likely explained the variable compositions of this latter group of RF. We positioned the observations of RF in a classic quantification of site type conditions (based on Estonian forest vegetation survey previously carried out by L~ohmus), which indicated that RF was more likely to occur on areas of higher soil fertility (in ordination space). Climatic and anthropogenic changes to RF create complex dynamic trends that are difficult to project into the future. Further research in tracing land use changes (using pollen analysis and documented evidence) should be utilized to refine the conceptual framework of ecosystem legacy and memory. Occurrence and frequency of deforestation and its characteristics as a novel disturbance regime are of particular interest.
Vitenskapelig – Is Marine Stewardship Council’s ecolabel a rising tide for all? Consumers’ willingness to pay for origin-differentiated ecolabeled canned tuna
Kar H. Lim, Wuyang Hu, Rodolfo M. Jr. Nayga
The Marine Stewardship Council's (MSC) sustainable seafood ecolabel covers about 10% of total seafood catch globally. Despite its prevalence, consumer willingness to pay (WTP) for MSC-certified imported seafood is not well understood. Using a choice experiment conducted with an American-consumers sample, this study measures the differences in WTP for American, Ecuadorian, and Vietnamese canned tuna. The results noted two things. First, the ecolabel induces country-specific effects, where the marginal WTP for the MSC label is higher for the imported products than for the domestic product; second, consumers prefer domestic products ceteris paribus, nevertheless, the premium of the ecolabel—when attached to the imported products—may partially eclipse preference for domestic products without the ecolabel. The results imply that the MSC ecolabel may generate a more favorable effect when applied to products from developing countries.
Vitenskapelig – Resilience of riparian vegetation after restoration measures on River Inn
M. Bauer, R. Harzer, K. Strobl, ...
River restoration is widely applied, although its effects are poorly understood, and degraded habitats might be difficult to improve. Moreover, there is a lack of monitoring as well as few systematic comparisons of restoration methods. This study presents results of a 4‐year monitoring on River Inn (southern Germany) investigating restoration by gravel or sand addition or embankment removal. The results were compared with reference sites that represent the pre‐restoration conditions. At the landscape scale, we analysed vegetation types based on aerial photographs, whereas at a smaller scale, we undertook vegetation surveys and evaluated species composition, growth, and life form, as well as the proportion of the target vegetation. After 4 years, the data indicated a “negative resilience” of the vegetation back to the state prior to restoration. The structural analysis revealed an extensive spread of reed at expense of bare soil. Thus, the species composition largely regressed to the pre‐restoration conditions, and neither annuals nor other pioneer species showed a long‐term benefit of river restoration. There were differences among the three restoration treatments after 2 years, but no longer after 4 years. However, the river restoration had three positive outcomes: (a) There was a temporary benefit for pioneer vegetation that most likely replenished the seed bank of the respective species, (b) the valuable reed communities showed resilience, and (c) the measures allowed some practical learning as expected for adaptive restoration.
Vitenskapelig – Effects of different blossom thinning agents on fruit set, yield, and fruit quality of ‘Jubileum’ European plum in a Nordic climate
Mekjell Meland, Milica Fotiric-Aksic, Dragan Radivojevic
European plums (Prunus domestica L.) blossom abundantly most years and often set too many flowers. If these excessive numbers of fruitlets remain on the trees until harvest, the crop would consist of small, unmarketable fruits of low fruit quality. Thinning agents like ammoniumthiosulphate (ATS), sulphur and soya oil desiccate flowers, especially stigma, which is the most sensitive tissue part of the flower. This way, the main effect of blossom thinning treatments is the disruption of pollination and fertilization. Thinning trials were conducted at a commercial orchard near the shore of the Hardangerfjord near Nibio Ullensvang, western Norway (60.2°N) on mature ‘Jubileum’ trees, all grafted on ‘St. Julien A’ rootstock. The trees were treated with 0.4, 0.8, 2 and 4% sulphur; a mixture of 0.4% sulphur + 2% soya oil and 1.5% ATS (liquid and powder formulations), at full bloom. All treatments were compared with hand-thinned and unthinned trees which were used as a control. Experimental trees were sprayed to the point of run-off with a hand sprayer during May 2008 and 2009 at full bloom. Flower thinners were efficient at relatively low temperatures which is a benefit in a cooler climate. In 2008 all thinning treatments reduced fruit set compared to unthinned controls for all cultivars. Sulphur and soya oil, both alone and in combination, were significantly less effective than ATS. In 2009, fruit set was higher and the effects of all thinning agents were lower. Fruit set decreased with increasing sulphur concentrations, but fruit thinning was not sufficient, even at the highest concentration. Both the liquid and powder formulations of ATS gave the same thinning effects. For all thinning treatments, both significant yield reductions and fruit weight increment were noticed during the experimental period. Fruit over color and soluble solids were generally higher and increased significantly with lower crop load, while fruit firmness (Durofel) and total acidity were less affected. In conclusion, different concentrations of sulphur had a moderate thinning effect and are not recommended for use as plum thinners under these conditions. Instead, 1.5% ATS application, (liquid and powder) applied at full bloom, resulted in adequate thinning of ’Jubileum’ plums under cool mesic northern climatic conditions.
Vitenskapelig – Rapid, nondestructive estimation of forest understory biomass using a handheld laser rangefinder
Mark J. Ducey, Rasmus Astrup
The forest understory is often associated with rapid rates of carbon and nutrient cycling, but cost-efficient quantification of its biomass remains challenging. We tested a new field technique for understory biomass assessment using an off-the-shelf handheld laser rangefinder. We conducted laser sampling in a pine forest with an understory dominated by invasive woody shrubs, especially Rhamnus frangula L. Laser sampling was conducted using a rangefinder, mounted on a monopod to provide a consistent reference height, and pointed vertically downward. Subsequently, the understory biomass was measured with destructive sampling. A series of metrics derived from the airborne LiDAR literature were evaluated alone and in combination for prediction of understory biomass using best-subsets regression. Resulting fits were good (r2 = 0.85 and 0.84 for the best single metric and best additive metric, respectively, and R2 = 0.93 for the best multivariate model). The results indicate that laser sampling could substantially reduce the need for costly destructive sampling within a double-sampling context.
Vitenskapelig – Thinning regimes and initial spacing for Eucalyptus plantations in Brazil
Antonio Carlos Ferraz Filho, Blas Mola-Yudego, José Ramón González-Olabarria, ...
This study focuses on the effects of different thinning regimes on clonal Eucalyptus plantations growth. Four different trials, planted in 1999 and located in Bahia and Espírito Santo States, were used. Aside from thinning, initial planting density, and post thinning fertilization application were also evaluated. Before canopy closure, and therefore before excessive competition between trees took place, it was found that stands planted under low densities (667 trees per hectare) presented a lower mortality proportion when compared to stand planted under higher densities (1111 trees per hectare). However, diameter growth prior to thinning operations was not statistically different between these two densities, presenting an overall mean of 4.9 cm/year. After canopy closure and the application of the thinning treatments, it was found that thinning regimes beginning early in the life of the stand and leaving a low number of residual trees presented the highest diameter and height growth. Unthinned treatments and thinning regimes late in the life of the stand (after 5.5 years), leaving a large number of residual trees presented the highest values of basal area production. The choice of the best thinning regime for Eucalyptus clonal material will vary according to the plantation objective.
Vitenskapelig – Tree, stand and site characteristics affecting the occurrence of lammas growth and multiple tops in field-grown Norway spruce
Aksel Granhus, Marek Metslaid, Harald Kvaalen, ...
In the Nordic-Baltic region, there has been a growing concern about an increasing occurrence of multiple tops in young stands of Norway spruce. There is however a lack of documentation on the amount of such damages, and the causal agents involved. In two separate studies in SE Norway, we assessed the frequency of multiple tops in young sapling-sized stands, and studied the relationship between the occurrence of multiple tops and lammas growth the previous growing season on the sample trees. Study 1 included 44 planted and 10 naturally regenerated stands, while Study 2 included 68 planted stands with information on seed source. Among sample trees with multiple tops, 57% (Study 1) and 32% (Study 2) had signs of lammas growth the previous autumn, either in the form of an extended leading shoot or swollen bud. Site index as well as sample tree height were positively correlated to the occurrence of both lammas growth and multiple tops in both studies. In Study 1 we show that the probability of lammas growth was significantly higher in planted than in naturally regenerated stands. In Study 2 we show that it was higher in stands planted with seedlings grown from stand-origin seeds compared with improved seed material. Furthermore, the results of both studies show that lammas growth occurs most frequently among the dominant trees in the stand.
Vitenskapelig – Four new Ophiostoma species associated with hardwood-infesting bark beetles in Norway and Poland
Truls Aas, Halvor Solheim, Robert Jankowiak, ...
Ophiostoma spp. (Ophiostomatales, Ascomycota) are well-known fungi associated with bark and ambrosia beetles (Curculionidae: Scolytinae, Platypodinae). Fungi in the Ophiostomatales include serious tree pathogens as well as agents of timber blue-stain. Although these fungi have been extensively studied in the northern hemisphere, very little is known regarding their occurrence on hardwoods in Europe. The aims of the present study were to identify and characterize new Ophiostoma spp. associated with bark and ambrosia beetles infesting hardwoods in Norway and Poland, and to resolve phylogenetic relationships of Ophiostoma spp. related to the Norwegian and Polish isolates, using multigene phylogenetic analyses. Results obtained from five gene regions (ITS, LSU, b-tubulin, calmodulin, translation elongation factor 1-a) revealed four new Ophiostoma spp. These include Ophiostoma hylesinum sp. nov., O. signatum sp. nov., and O. villosum sp. nov. that phylogenetically are positioned within the Ophiostoma ulmi complex. The other new species, Ophiostoma pseudokarelicum sp. nov. reside along with Ophiostoma karelicum in a discrete, well-supported phylogenetic group in Ophiostoma s. stricto. The results of this study clearly show that the diversity and ecology of Ophiostoma spp. on hardwoods in Europe is poorly understood and that further studies are required to enrich our knowledge about these fungi.
Vitenskapelig – Contrasting biosphere responses to hydrometeorological extremes: revisiting the 2010 western Russian heatwave
Milan Flach, Sebastian Sippel, Fabian Gans, ...
Combined droughts and heatwaves are among those compound extreme events that induce severe impacts on the terrestrial biosphere and human health. A record breaking hot and dry compound event hit western Russia in summer 2010 (Russian heatwave, RHW). Events of this kind are relevant from a hydrometeorological perspective, but are also interesting from a biospheric point of view because of their impacts on ecosystems, e.g., reductions in the terrestrial carbon storage. Integrating both perspectives might facilitate our knowledge about the RHW. We revisit the RHW from both a biospheric and a hydrometeorological perspective. We apply a recently developed multivariate anomaly detection approach to a set of hydrometeorological variables, and then to multiple biospheric variables relevant to describe the RHW. One main finding is that the extreme event identified in the hydrometeorological variables leads to multidirectional responses in biospheric variables, e.g., positive and negative anomalies in gross primary production (GPP). In particular, the region of reduced summer ecosystem production does not match the area identified as extreme in the hydrometeorological variables. The reason is that forest-dominated ecosystems in the higher latitudes respond with unusually high productivity to the RHW. Furthermore, the RHW was preceded by an anomalously warm spring, which leads annually integrated to a partial compensation of 54% (36% in the preceding spring, 18% in summer) of the reduced GPP in southern agriculturally dominated ecosystems. Our results show that an ecosystem-specific and multivariate perspective on extreme events can reveal multiple facets of extreme events by simultaneously integrating several data streams irrespective of impact direction and the variables' domain. Our study exemplifies the need for robust multivariate analytic approaches to detect extreme events in both hydrometeorological conditions and associated biosphere responses to fully characterize the effects of extremes, including possible compensatory effects in space and time.
Vitenskapelig – The ash dieback invasion of Europe was founded by two genetically divergent individuals
Mark McMullan, Maryam Rafiqi, Gemy Kaithakottil, ...
Accelerating international trade and climate change make pathogen spread an increasing concern. Hymenoscyphus fraxineus, the causal agent of ash dieback, is a fungal pathogen that has been moving across continents and hosts from Asian to European ash. Most European common ash trees (Fraxinus excelsior) are highly susceptible to H.fraxineus, although a minority (~5%) have partial resistance to dieback. Here, we assemble and annotate a H.fraxineus draft genome, which approaches chromosome scale. Pathogen genetic diversity across Europe and in Japan, reveals a strong bottleneck in Europe, though a signal of adaptive diversity remains in key host interaction genes. We find that the European population was founded by two divergent haploid individuals. Divergence between these haplotypes represents the ancestral polymorphism within a large source population. Subsequent introduction from this source would greatly increase adaptive potential of the pathogen. Thus, further introgression of H.fraxineus into Europe represents a potential threat and Europe-wide biological security measures are needed to manage this disease.
Vitenskapelig – Microalgal Bioactive Compounds Including Protein, Peptides, and Pigments: Applications, Opportunities, and Challenges During Biorefinery Processes
Maria Hayes, Leen Bastiaens, Luisa Gouveia, ...
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Vitenskapelig – Reproducción y efecto nocivo de Meloidogyne incognita (Kofoid y White) Chitwood en Phaseolus vulgaris L. ‛Cuba-Cueto-25-9’
Dainé Hernández-Ochandia, Mayra G. Rodríguez-Hernández, Ileana Miranda-Cabrera, ...
El objetivo del estudio fue determinar el factor de reproducción (FR) de Meloidogyne incognita (Kofoid y White) Chitwood y el efecto nocivo del nematodo sobre parámetros seleccionados del desarrollo de las plantas de frijol (Phaseolus vulgaris L.) cultivar ‛Cuba Cueto 25-9’. El experimento se realizó, en condiciones semicontroladas, durante 35 días, con niveles poblacionales iniciales (Pi) de 1,5; 2,5 y 5 juveniles de segundo estadio (J2) y huevos del nematodo por gramo de sustrato y plantas de frijol sin nematodos (testigos). Se determinó el Factor de Reproducción (FR) del nematodo y en la planta se evaluaron el Índice de Agallamiento (IA), la altura de las plantas, el diámetro del tallo, el número de hojas, flores y legumbres. Los datos se analizaron y compararon (ANOVA, Duncan (p<0,05)) y la relación entre la altura de las plantas y Pi se determinó a través de análisis de regresión, empleando el Paquete Estadístico SAS, Versión 9.0. El nematodo parasitó y se reprodujo en el cultivar de frijol ‛CC- 25-9’ con valores de FR=1,6; 6,1 y 6,2 y del IA=3; 3,6 y 3,8 en los niveles de Pi=1,5; 2,5 y 5 J2-huevos x gramo de sustrato-1, respectivamente. Con el incremento de la Pi del nematodo se redujo, significativamente, la altura de las plantas del cultivar ‛CC 25-9’ (R2=0.70). El nematodo produjo disminuciones, no significativas, del diámetro del tallo, número de hojas, flores y legumbres; sin embargo, se evidenció una tendencia a que los mayores valores de los parámetros evaluados se presentaron en las plantas sanas. Se discute la importancia de utilizar plantas de la misma familia al momento de evaluar resistencia/susceptibilidad de cultivares frente a Meloidogyne spp.
Vitenskapelig – Genetic yield gains of winter wheat in Germany over more than 100 years (1895-2007) under contrasting fertilizer applications
Hella Ellen Ahrends, Werner Eugster, Thomas Gaiser, ...
For highly productive regions such as Germany, the increase of wheat grain yields observed throughout the 20th century is largely attributed to the progress in crop breeding and agronomic management. However, several studies indicate a strong variability of the genetic contribution across locations that further varies with experimental design and variety selection. It is therefore still unclear to which extent management conditions have promoted the realization of the breeding progress in Germany over the last 100+ years. We established a side-by-side cultivation experiment over two seasons(2014/2015 and 2015/2016)including 16 winter wheat varieties released in Germany between 1895 and 2007. The varieties were grown using 24 different long-term fertilization treatments established since 1904 (Dikopshof, Germany). Averaged over all cultivars and treatments mean yields of 6.88 t ha−1 and 5.15 t ha−1were estimated in 2015 and 2016, respectively. A linear mixed effects analysis was performed to study the treatment-specific relation between grain yields and year of variety release. Results indicate a linear increase in grain yields ranging from 0.025 to 0.032 t ha−1 yr−1 (0.304 to 0.387% yr−1 )in plots that were treated with combined synthetic-organic fertilizers without signs of a leveling-off. Yields from low or unfertilized plots do not show a significant progress in yield. Responsiveness of mean yields to fertilizer management increases with year of release and indicates small yield penalties under very low nutrient supply. Results highlight the need to consider the importance of long-term soil fertilization management for the realization of genetic gains and the value of long-term fertilization experiments to study interactions between genetic potential and management.
Vitenskapelig – Integrated, spatial distributed modelling of surface runoff and soil erosion during winter and spring
Torsten Starkloff, Jannes Stolte, Rudi Hessel, ...
In cold climate regions a significant fraction of annual soil erosion in agricultural land occurs during snowmelt and rain on partially frozen soils. Physically based and spatially distributed soil erosion models have proved to be good tools for understanding the processes occurring at catchment scale during rainfall erosion. However, most existing erosion models do not account for snow in a suitable way. A combination of the UEBGrid snow pack model and the LISEM erosion model was therefore used in this study. The aim was to test and validate this model combination and to assess its utility in relation to quantification and process understanding. Applying this model combination to simulate surface runoff and soil erosion showed that, in principle, it is possible to satisfactorily simulate surface runoff and observed soil erosion patterns during winter. The values for the calibration parameters were similar for the two chosen winter periods when the rainfall and snowmelt episodes occurred. However, the calibration procedure showed that the utility of this combination had several limitations. It is hoped that this study can help to improve existing models and trigger new developments in including snow pack dynamics and soil freezing and thawing in soil erosion models.
Vitenskapelig – Miscanthus Biochar had Limited Effects on Soil Physical Properties, Microbial Biomass, and Grain Yield in a Four-Year Field Experiment in Norway
Adam O.Toole, Christophe Moni, Simon Weldon, ...
The application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we conducted a four-year field experiment between October 2010 to October 2014 on a fertile silty clay loam Albeluvisol in Norway to assess the impact of biochar on soil physical properties, soil microbial biomass, and oat and barley yield. The following treatments were included: Control (soil), miscanthus biochar 8 t C ha1 (BC8), miscanthus straw feedstock 8 t C ha1 (MC8), and miscanthus biochar 25 t C ha1 (BC25). Average volumetric water content at field capacity was significantly higher in BC25 when compared to the control due to changes in BD and total porosity. The biochar amendment had no effect on soil aggregate (2–6 mm) stability, pore size distribution, penetration resistance, soil microbial biomass C and N, and basal respiration. Biochar did not alter crop yields of oat and barley during the four growing seasons. In order to realize biochar’s climate mitigation potential, we suggest future research and development efforts should focus on improving the agronomic utility of biochar in engineered fertilizer and soil amendment products.
Vitenskapelig – Analysing Farm-specific Payments for Norway using the Agrispace Model
Klaus Mittenzwei, Wolfgang Britz
Norway maintains a complex system of activity or type specific coupled paymentswhich account for a large share of farm income. Most of the payment rates arenegatively related to farm size and are higher in remote areas compared to centralregions. We present and use a newly developed recursive-dynamic multi-commoditymodel (Agrispace) with CES production functions depicting regional farm clustersderived from the full farm population. Using this model, we simulate impacts ofcurrent and alternative subsidy policies on production, prices, input use, incomeand farm structural change. Mapping cluster results to each farm along with beha-vioural rules allows estimation of individual profits and farm exits. Our results indi-cate that, in the short run, the current policy regime seems to support the policyobjective of maintaining a variety of farms in all parts of Norway. In the long run,farm structural change is less affected by a policy reform that leaves total supportlevels unchanged.
Vitenskapelig – Accelerated increase in plant species richness on mountain summits is linked to warming
Manuel J. Steinbauer, John-Arvid Grytnes, Gerald Jurasinski, ...
Globally accelerating trends in societal development and human environmental impacts since the mid-twentieth century1–7 are known as the Great Acceleration and have been discussed as a key indicator of the onset of the Anthropocene epoch6 . While reports on ecological responses (for example, changes in species range or local extinctions) to the Great Acceleration are multiplying8,9 , it is unknown whether such biotic responses are undergoing a similar acceleration over time. This knowledge gap stems from the limited availability of time series data on biodiversity changes across large temporal and geographical extents. Here we use a dataset of repeated plant surveys from 302 mountain summits across Europe, spanning 145 years of observation, to assess the temporal trajectory of mountain biodiversity changes as a globally coherent imprint of the Anthropocene. We find a continent-wide acceleration in the rate of increase in plant species richness, with five times as much species enrichment between 2007 and 2016 as fifty years ago, between 1957 and 1966. This acceleration is strikingly synchronized with accelerated global warming and is not linked to alternative global change drivers. The accelerating increases in species richness on mountain summits across this broad spatial extent demonstrate that acceleration in climate-induced biotic change is occurring even in remote places on Earth, with potentially far-ranging consequences not only for biodiversity, but also for ecosystem functioning and services.
Vitenskapelig – A review of regulations and guidelines related to winter manure application
Jian Liu, Peter J. A. Kleinman, Helena Aronsson, ...
Winter manure application elevates nutrient losses and impairment of water quality as compared to manure applications in other seasons. In conjunction with reviewing global distribution of animal densities, we reviewed worldwide mandatory regulations and voluntary guidelines on efforts to reduce off-site nutrient losses associated with winter manure applications. Most of the developed countries implement regulations or guidelines to restrict winter manure application, which range from a regulative ban to guidelines based upon weather and field management conditions. In contrast, developing countries lack such official directives, despite an increasing animal production industry and concern over water quality. An analysis of five case studies reveals that directives are derived from a common rationale to reduce off-site manure nutrient losses, but they are also affected by local socioeconomic and biophysical considerations. Successful programs combine site-specific management strategies along with expansion of manure storage to offer farmers greater flexibility in winter manure management.
Vitenskapelig – Mulching with coffee husk and pulp in strawberry affects edaphic predatory mite and spider mite densities
Fernanda de Cássia Neves Esteca, Luis Rodolfo Rodrigues, Gilberto José de Moraes, ...
Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants—Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.
Vitenskapelig – An examination of the potential for the use of the Maillard reaction to modify wood
K. Peeters, Erik Larnøy, Andreja Kutnar, ...
Finding efficient ways to decrease wood decay caused by fungi is an important issue in the timber construction. A possible way to avoid wood decay by fungi is by reducing the water content of wood, since water is a primary condition for fungal growth. Bulking of the wood cell wall by chemical reagents occupies the space where water normally occurs. This also improves the dimensional stability of the modified wood. The aim of the work was to react non-toxic reagents using a Maillard type of reaction in the wood cell wall. Wood was soaked in different aqueous solutions with a primary amine and a sugar as the main constituents. The wood was thereafter cured in an oven at 120°C. The preliminary results showed that the use of the Maillard reaction for wood modification is a promising method and is worth further research.
Vitenskapelig – Abscisic acid regulates anthocyanin biosynthesis and gene expression associated with cell wall modification in ripening bilberry (vaccinium myrtillus l.) fruits
Katja Hannele Karppinen, Pinja Tegelberg, Hely Häggman, ...
Ripening of non-climacteric bilberry (Vaccinium myrtillus L.) fruit is characterized by a high accumulation of health-beneficial anthocyanins. Plant hormone abscisic acid (ABA) and sucrose have been shown to be among the central signaling molecules coordinating non-climacteric fruit ripening and anthocyanin accumulation in some fruits such as strawberry. Our earlier studies have demonstrated an elevation in endogenous ABA level in bilberry fruit at the onset of ripening indicating a role for ABA in the regulation of bilberry fruit ripening. In the present study, we show that the treatment of unripe green bilberry fruits with exogenous ABA significantly promotes anthocyanin biosynthesis and accumulation both in fruits attached and detached to the plant. In addition, ABA biosynthesis inhibitor, fluridone, delayed anthocyanin accumulation in bilberries. Exogenous ABA also induced the expression of several genes involved in cell wall modification in ripening bilberry fruits. Furthermore, silencing of VmNCED1, the key gene in ABA biosynthesis, was accompanied by the down-regulation in the expression of key anthocyanin biosynthetic genes. In contrast, the treatment of unripe green bilberry fruits with exogenous sucrose or glucose did not lead to an enhancement in the anthocyanin accumulation neither in fruits attached to plant nor in post-harvest fruits. Moreover, sugars failed to induce the expression of genes associated in anthocyanin biosynthesis or ABA biosynthesis while could elevate expression of some genes associated with cell wall modification in post-harvest bilberry fruits. Our results demonstrate that ABA plays a major role in the regulation of ripening-related processes such as anthocyanin biosynthesis and cell wall modification in bilberry fruit, whereas sugars seem to have minor regulatory roles in the processes. The results indicate that the regulation of bilberry fruit ripening differs from strawberry that is currently considered as a model of nonclimacteric fruit ripening. In this study, we also identified transcription factors, which expression was enhanced by ABA, as potential regulators of ABA-mediated bilberry fruit ripening processes.
Vitenskapelig – Brown-rot fungal degradation and de-acetylation of acetylated wood
Greeley Beck, Emil Engelund Thybring, Lisbeth Garbrecht Thygesen
Earlywood samples of unmodified and acetylated radiata pine were exposed to the brown-rot fungus Rhodonia placenta for 1, 2, 3 and 4 weeks for unmodified samples and 10, 16, 24 and 28 weeks for acetylated samples. Longer incubation periods were used for acetylated samples based on the hypothesis that given enough time under favourable conditions the fungus would eventually degrade the wood. After exposure, samples were weighed and chemically characterized by ATR-FTIR analysis, acetyl content by saponification, and hydroxyl (OH) accessibility by deuterium exchange. Longer incubation times for acetylated samples led to comparable levels of mass loss between unmodified and acetylated wood. Initial brown-rot decay in acetylated wood exhibited a different trend compared to unmodified wood, with an increased OH accessibility and a significant reduction in acetyl content. This was followed by a stable, low OH accessibility and plateau in acetyl content above 10% mass loss in acetylated wood. In unmodified wood, the OH accessibility was nearly constant throughout decay, while the initially low acetyl content decreased linearly with mass loss. ATR-FTIR analysis confirmed the differences in acetyl removal between unmodified and acetylated wood. Wood-water relations before and after brown-rot decay were determined with low-field nuclear magnetic resonance (LFNMR) relaxometry on water saturated samples. For the decayed acetylated wood, the behaviour of the water corresponded well with de-acetylation observed by chemical characterization. The results show that after removal of acetyl groups, degradation of acetylated wood by R. placenta occurred at a similar rate to that of unmodified wood.
Vitenskapelig – Continental-scale macrofungal assemblage patterns correlate with climate, soil carbon and nitrogen deposition
Carrie Joy Andrew, Rune Halvorsen, Einar Heegaard, ...
Aim:Macroecological scales of species compositional trends are well documentedfor a variety of plant and animal groups, but remain sparse for fungi, despite theirecological importance in carbon and nutrient cycling. It is, thus, essential to under-stand the composition of fungal assemblages across broad geographical scales andthe underlying drivers. Our overall aim was to describe these patterns for fungiacross two nutritional modes (saprotrophic and ectomycorrhizal). Furthermore, weaimed to elucidate the temporal component of fruiting patterns and to relate theseto soil carbon and nitrogen deposition. Location:Central and Northern Europe.Methods:A total of 4.9 million fungal fruit body observations throughout Europe,collected between 1970 and 2010, were analysed to determine the two main envi-ronmental and geographical gradients structuring fungal assemblages for two mainnutritional modes, saprotrophic and ectomycorrhizal fungi. Results:Two main gradients explaining the geography of compositional patternswere identified, for each nutritional mode. Mean annual temperature (and relatedcollinear, seasonal measures) correlated most strongly with the first gradient forboth nutritional modes. Soil organic carbon was the highest correlate of the second compositional gradient for ectomycorrhizal fungi, suspected as an indicator of vege-tation- and pH-related covariates. In contrast, nitrogen deposition constituted asecond gradient for saprotrophic fungi, likely a proxy for anthropogenic pollution.Compositional gradients and environmental conditions correlated similarly whenthe data were divided into two time intervals of 1970–1990 and 1991–2010.Evidence of compositional temporal change was highest with increasing elevationand latitude. Main conclusions:Fungal assemblage patterns demonstrate clear biogeographicalpatterns that relate the nutritional modes to their main environmental correlates oftemperature, soil organic carbon and nitrogen deposition. With respect to globalchange impacts, the highest rates of compositional change by time suggest targetinghigher latitudes and elevations for a better understanding of fungal dynamics. We,finally, suggest further examination of the ranges and dispersal abilities of fungi tobetter assess responses to global change.
Vitenskapelig – Acetylation of Pinus radiata delays hydrolytic depolymerisation by the brown-rot fungus Rhondonia placenta
Harold Greeley Beck, Olav Aaseth Hegnar, Carl Gunnar Fossdal, ...
Acetylation of wood can provide protection against wood deteriorating fungi, but the exact degradation me- chanism remains unclear. The aim of this study was to determine the eﬀect of acetylation of Pinus radiata wood (weight percent gain 13, 17 and 21%) on the expression of genes involved in decay by brown-rot fungus Rhodonia placenta. Gene expression analysis using qRT-PCR captured incipient to advanced decay stages. As expected the initiation of decay was delayed as a result the degree of acetylation. However, once decay was established, the rate of degradation in acetylated samples was similar to that of unmodi ﬁed wood. This suggests a delay in decay rather than an absolute protection threshold at higher acetylation levels. In accordance with previous studies, the oxidative system of R. placenta was more active in wood with higher degrees of acetylation and expression of cellulose active enzymes was delayed for acetylated samples compared to untreated samples. The reason for the delay in the latter might be because of the slower diﬀusion rate in acetylated wood or that partially acetylated cellobiose may be less eﬀective in triggering production of sacchariﬁcation enzymes. Enzymes involved in hemicellulose and pectin degradation have previously not been focused on in studies of degradation of acetylated wood. Surprisingly, CE16 carbohydrate esterase, assumed to be involved in deace- tylation of carbohydrates, was expressed signiﬁcantly more in untreated samples compared to highly acetylated samples. We hypothesise that this enzyme might be regulated through a negative feedback system, where acetic acid supresses the expression. The up-regulation of two expansin genes in acetylated samples suggests that their function, to loosen the cell wall, is needed more in acetylated wood due the physical bulking of the cell wall. In this study, we demonstrate that acetylation aﬀects the expression of speciﬁc target genes not previously re- ported, resulting in delayed initiation of decay. Thus, targeting these degradation mechanisms can contribute to improving wood protection systems.
Vitenskapelig – Route of exposure has a major impact on uptake of silver nanoparticles in Atlantic salmon (Salmo salar)
Merethe Kleiven, Bjørn O Rosseland, Hans-Christian Teien, ...
The potential impact of silver nanoparticles (Ag NPs) on aquatic organisms is to a large extent determined by theirbioavailability through different routes of exposure. In the present study juvenile Atlantic salmon (Salmo salar) were exposed todifferent sources of radiolabeled Ag (radiolabeled110mAg NPs and110mAgNO3). After 48 h of waterborne exposure to 3mg/Lcitrate stabilized110mAg NPs or110mAgNO3, or a dietary exposure to 0.6mg Ag/kg fish (given as citrate stabilized or uncoated110mAg NPs, or110mAgNO3), Ag had been taken up in fish regardless of route of exposure or source of Ag (Ag NPs or AgNO3).Waterborne exposure led to high Ag concentrations on the gills, and dietary exposure led to high concentrations in thegastrointestinal tract. Silver distribution to the target organs was similar for both dietary and waterborne exposure, with the liveras the main target organ. The accumulation level of Ag was 2 to 3 times higher for AgNO3than for Ag NPs when exposure wasthrough water, whereas no significant differences were seen after dietary exposure. The transfer (Bq/g liver/g food or water)from exposure through water was 4 orders of magnitude higher than from feed using the smallest, citrate-stabilized Ag NPs(4 nm). The smallest NPs had a 5 times higher bioavailability in food compared with the larger and uncoated Ag NPs (20 nm).Despite the relatively low transfer of Ag from diet to fish, the short lifetime of Ag NPs in water and their transfer to sediment,feed, or sediment-dwelling food sources such as larvae and worms could make diet a significant long-term exposure route.
Vitenskapelig – Genetic evidence of female kin clusters in a continuous population of a solitary carnivore, the Eurasian lynx
Katja Holmala, Annika Herrero, Alexander Kopatz, ...
Large terrestrial carnivores can sometimes display strong family bonds affecting the spatial distribution of related individuals. We studied the spatial genetic relatedness and family structure of female Eurasian lynx, continuously distributed in southern Finland. We hypothesized that closely related females form matrilineal assemblages, clustering together with relatives living in the neighboring areas. We evaluated this hypothesis using tissue samples of 133 legally harvested female lynx (from year 2007 to 2015), genotyped with 23 microsatellite markers, and tested for possible spatial genetic family structure using a combination of Bayesian clustering, spatial autocor ‐ relation, and forensic genetic parentage analysis. The study population had three potential family genetic clusters, with a high degree of admixture and geographic overlap, and showed a weak but significant negative relationship between pairwise genetic and geographic distance. Moreover, parentage analysis indicated that 64% of the females had one or more close relatives (sister, mother, or daughter) within the study population. Individuals identified as close kin consistently assigned to the same putative family genetic cluster. They also were sampled closer geographically than females on average, although variation was large. Our results support the possibility that Eurasian lynx forms matrilineal assemblages, and comparisons with males are now required to further assess this hypothesis.
Vitenskapelig – Copper pollution exacerbates the effects of ocean acidification and warming on kelp microscopic early life stages
Pablo P. Leal, Catriona L. Hurd, Sylvia G. Sander, ...
Ocean warming (OW), ocean acidification (OA) and their interaction with local drivers, e.g., copper pollution, may negatively affect macroalgae and their microscopic life stages. We evaluated meiospore development of the kelps Macrocystis pyrifera and Undaria pinnatifida exposed to a factorial combination of current and 2100-predicted temperature (12 and 16 °C, respectively), pH (8.16 and 7.65, respectively), and two copper levels (no-added-copper and species-specific germination Cu- EC50). Meiospore germination for both species declined by 5–18% under OA and ambient temperature/ OA conditions, irrespective of copper exposure. Germling growth rate declined by >40%·day−1, and gametophyte development was inhibited under Cu-EC50 exposure, compared to the no-added-copper treatment, irrespective of pH and temperature. Following the removal of copper and 9-day recovery under respective pH and temperature treatments, germling growth rates increased by 8–18%·day−1. The exception was U. pinnatifida under OW/OA, where growth rate remained at 10%·day−1 before and after copper exposure. Copper-binding ligand concentrations were higher in copper-exposed cultures of both species, suggesting that ligands may act as a defence mechanism of kelp early life stages against copper toxicity. Our study demonstrated that copper pollution is more important than global climate drivers in controlling meiospore development in kelps as it disrupts the completion of their life cycle.
Vitenskapelig – Experimental evaluation of the robustness of the growth-stress tolerance trade-off within the perennial grass Dactylis glomerata
Pauline Bristiel, Lauren Gillespie, Liv Østrem, ...
1. A core tenet of functional ecology is that the vast phenotypic diversity observed in the plant kingdom could be partly generated by a trade-off between the ability of plants to grow quickly and acquire resources in rich environments vs. the ability to conserve resources and avoid mortality under stress. However, experimental demonstrations remain scarce and potentially blurred by phylogenetic constraints in cross-species analyses. Here, we experimentally decoupled growth potential and stress survival by applying an off-season stress on contrasting populations of the perennial grass Dactylis glomerata exhibiting a range of seasonal dormancy.2. Seventeen populations of D. glomerata, originating from a latitudinal gradient from Norway to Morocco, were subjected to three types of dehydration stress: winter frost in Norway, and summer drought and early spring (off-season) drought stress in the south of France. Growth rate and two leaf traits (leaf width and leaf dry matter content) suspected to be involved in the adaptation to dehydration stress were monitored under optimal conditions. We quantified plant dehydration survival as the amount of plant recovery after a severe stress.3. Nordic populations were found to be winter-dormant. Winter- and summer-dor-mant populations better survived frost and summer drought, respectively. However, no trade-off between growth potential and dehydration survival was detected in non-dormant plants in early spring when dehydration occurred unsea-sonably for all populations. Furthermore, Mediterranean populations better survived an early spring drought.4. Our results highlight the importance of assessing plant growth potential as a re-sponse to seasonal environmental cues. They suggest that growth potential and stress survival trade off when plants exhibit seasonal dormancy but can be func-tionally independent at other seasons. Consequently, the growth–stress survival relationship could be better described as a dynamic linkage rather than a constant and general trade-off. Moreover, leaf trait values, such as thinner and more ligni-fied leaves reflecting drought adaptation, may have contributed to the improved drought-stress survival without resulting in a cost to growth. 5. Further exploration of the growth–stress survival relationship should permit deci-phering the suite of plant traits and trait covariations involved in plants’ responses to increasing stress.
Vitenskapelig – Establishment of the fungal entomopathogen Beauveria bassiana as an endophyte in sugarcane, Saccharum officinarum
Trust Kasambala, Fernando E. Vega, Ingeborg Klingen
We investigated the ability of the fungal entomopathogen Beauveria bassiana strain GHA to endophytically colonize sugarcane (Saccharum officinarum) and its impact on plant growth. We used foliar spray, stem injection, and soil drench inoculation methods. All three inoculation methods resulted in B. bassiana colonizing sugarcane tissues. Extent of fungal colonization differed significantly with inoculation method (χ2 = 20.112, d. f. = 2, p < 0.001), and stem injection showed the highest colonization level followed by foliar spray and root drench. Extent of fungal colonization differed significantly with plant part (χ2 = 33.072, d. f. = 5, p < 0.001); stem injection resulted in B. bassiana colonization of the stem and to some extent leaves; foliar spray resulted in colonization of leaves and to some extent, the stem; and soil drench resulted in colonization of roots and to some extent the stem. Irrespective of inoculation method, B. bassiana colonization was 2.8 times lower at 14–16 d post inoculation (DPI) than at 7–10 DPI (p = 0.020). Spraying leaves and drenching the soil with B. bassiana significantly (p = 0.01) enhanced numbers of sett roots. This study demonstrates for the first time that B. bassiana can endophytically colonize sugarcane plants and enhance the root sett and it provides a starting point for exploring the use of this fungus as an endophyte in management of sugarcane pests.
Vitenskapelig – Three new Leptographium spp. (Ophiostomatales) infecting hardwood trees in Norway and Poland
Robert Jankowiak, Agnieszka Ostafińska, Truls Aas, ...
Species of Leptographium are characterized by mononematous or synnematous conidiophores and are commonly associated with different arthropods. Some of them also produce a sexual state characterised by globose ascomata with elongated necks. Compared to investigations on coniferous trees, the occurrence of Leptographium species on hardwood trees has been poorly studied in Europe. During a survey of ophiostomatoid fungi on various hardwood tree species in Norway and Poland, three unusual species, which fit in the broader morphological description of Leptographium spp., were found in association with Trypodendron domesticum, Trypodendron signatum and Dryocoetes alni, and from wounds on a variety of hardwoods. Phylogenetic analyses of sequence data for six different loci (ITS1–5.8 S–ITS2, ITS2-LSU, ACT, b-tubulin, CAL, and TEF-1a) showed that these Leptographium species are phylogenetically closely related to the species of the Grosmannia olivacea complex. The first species forms a well-supported lineage that includes Ophiostoma brevicolle, while the two other new taxa resided in a separate lineage; possibly affiliated with Grosmannia francke-grosmanniae. All the new species produce perithecia with necks terminating in ostiolar hyphae and orange-section shaped ascospores with cucullate, gelatinous sheaths. These species also produce dark olivaceous mononematous asexual states in culture. In addition, two of the newly described species have a second type of conidiophore with a short and non-pigmented stipe. The new Leptographium species can be easily distinguished from each other by their appearance and growth in culture. Based on novel morphological characters and distinct DNA sequences, these fungi were recognised as new taxa for which the names Leptographium tardum sp. nov., Leptographium vulnerum sp. nov., and Leptographium flavum sp. nov. are provided.
Vitenskapelig – Respiration rate and changes in composition of volatiles during short-term storage of minimally processed root vegetables
Haakon Helland, A Leufvén, Gunnar Bengtsson, ...
Preliminary results on aroma profiles (GC-MS) related to storage conditions (temperature, time and packaging atmosphere) are presented. The vegetables used in the experiments were rutabaga, carrot and turnip, which were peeled and cut before packaging, and stored at two different temperatures. O2 and CO2 concentrations in the packaging atmosphere were measured during the storage period to calculate the respiration rates of the produce. Cubed carrot showed a higher respiration rate than cubed turnip and rutabaga. Samples for analysis of volatiles were taken after 0 and 7 or 10 days. This type of analysis could be used as a complement to sensory analysis.
Vitenskapelig – Bioinformatic characterisation of the effector repertoire of the strawberry pathogen Phytophthora cactorum
Andrew D. Armitage, Erik Lysøe, Charlotte F. Nellist, ...
The oomycete pathogen Phytophthora cactorum causes crown rot, a major disease of cultivated strawberry. We report the draft genome of P. cactorum isolate 10300, isolated from symptomatic Fragaria x ananassa tissue. Our analysis revealed that there are a large number of genes encoding putative secreted effectors in the genome, including nearly 200 RxLR domain containing effectors, 77 Crinklers (CRN) grouped into 38 families, and numerous apoplastic effectors, such as phytotoxins (PcF proteins) and necrosis inducing proteins. As in other Phytophthora species, the genomic environment of many RxLR and CRN genes differed from core eukaryotic genes, a hallmark of the two-speed genome. We found genes homologous to known Phytophthora infestans avirulence genes including Avr1, Avr3b, Avr4, Avrblb1 and AvrSmira2 indicating effector sequence conservation between Phytophthora species of clade 1a and clade 1c. The reported P. cactorum genome sequence and associated annotations represent a comprehensive resource for avirulence gene discovery in other Phytophthora species from clade 1 and, will facilitate effector informed breeding strategies in other crops.
Vitenskapelig – GrassPlot – a database of multi-scale plant diversity in Palaearctic grasslands
Jürgen Dengler, Viktoria Wagner, Iwona Dembicz, ...
GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (relevés) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001; ... 1,000 m²) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database “sPlot”. Its main aim is to facilitate studies on the scale- and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board.
Vitenskapelig – Enhancing the Water Accounting and Vulnerability Evaluation Model: WAVE+
Markus Berger, Stephanie Eisner, Ruud van der Ent, ...
Due to the increasing relevance of analyzing water consumption along product life cycles, the water accounting and vulnerability evaluation model (WAVE) has been updated and methodologically enhanced. Recent data from the atmospheric moisture tracking model WAM2-layers is used to update the basin internal evaporation recycling (BIER) ratio, which denotes atmospheric moisture recycling within drainage basins. Potential local impacts resulting from water consumption are quantified by means of the water deprivation index (WDI). Based on the hydrological model WaterGAP3, WDI is updated and methodologically refined to express a basin’s vulnerability to freshwater deprivation resulting from the relative scarcity and absolute shortage of water. Compared to the predecessor version, BIER and WDI are provided on an increased spatial and temporal (monthly) resolution. Differences compared to annual averages are relevant in semiarid and arid basins characterized by a high seasonal variation of water consumption and availability. In order to support applicability in water footprinting and life cycle assessment, BIER and WDI are combined to an integrated WAVE+ factor, which is provided on different temporal and spatial resolutions. The applicability of the WAVE+ method is proven in a case study on sugar cane, and results are compared to those obtained by other impact assessment methods.
Vitenskapelig – An enhanced forest classification scheme for modeling vegetation–climate interactions based on national forest inventory data
Titta Majasalmi, Stephanie Eisner, Rasmus Astrup, ...
Forest management affects the distribution of tree species and the age class of a forest, shaping its overall structure and functioning and in turn the surface–atmosphere exchanges of mass, energy, and momentum. In order to attribute climate effects to anthropogenic activities like forest management, good accounts of forest structure are necessary. Here, using Fennoscandia as a case study, we make use of Fennoscandic National Forest Inventory (NFI) data to systematically classify forest cover into groups of similar aboveground forest structure. An enhanced forest classification scheme and related lookup table (LUT) of key forest structural attributes (i.e., maximum growing season leaf area index (LAImax), basal-area-weighted mean tree height, tree crown length, and total stem volume) was developed, and the classification was applied for multisource NFI (MSNFI) maps from Norway, Sweden, and Finland. To provide a complete surface representation, our product was integrated with the European Space Agency Climate Change Initiative Land Cover (ESA CCI LC) map of present day land cover (v.2.0.7). Comparison of the ESA LC and our enhanced LC products (https://doi.org/10.21350/7zZEy5w3) showed that forest extent notably (κ = 0.55, accuracy 0.64) differed between the two products. To demonstrate the potential of our enhanced LC product to improve the description of the maximum growing season LAI (LAImax) of managed forests in Fennoscandia, we compared our LAImax map with reference LAImax maps created using the ESA LC product (and related cross-walking table) and PFT-dependent LAImax values used in three leading land models. Comparison of the LAImax maps showed that our product provides a spatially more realistic description of LAImax in managed Fennoscandian forests compared to reference maps. This study presents an approach to account for the transient nature of forest structural attributes due to human intervention in different land models.
Vitenskapelig – Morning and evening pasture access – comparing the effect of production pasture and exercise pasture on milk production and cow behaviour in an automatic milking system
Haldis Kismul, Eva Spörndly, Mats Höglind, ...
Although pasture is low-cost feed, many farmers ﬁnd it diﬃcult to maintain high milk yield when using pasturefor high-yielding dairy cows in automatically milked herds. Therefore, a seven-week experiment with 40 cows inearly to mid-lactation was performed to evaluate a management model for including pasture in the diet withoutjeopardizing milk production. Within a part-time grazing system with morning and evening outdoor access, wecompared a group with ad libitum grass silage indoors combined with access to a small grass-covered permanentpaddock for exercise and recreation (group EX) with a group oﬀered production pasture at a high allowance percow and day combined with restricted grass silage allowance at night (group PROD). Both groups had the sameoutdoor access times and the same concentrate allowance based on pre-experimental milk yield. Milk yield andmilking frequency were recorded daily in the automatic milking unit. Milk recordings and samplings for de-termination of milk composition took place weekly and outdoor behaviour of cows was recorded during pastureaccess hours on six observation days, evenly distributed over the experimental period. During the experiment,average metabolisable energy concentration was higher in the grass silage oﬀered both groups than in pastureherbage. However, our results showed no signiﬁcant diﬀerence in daily milk yield between treatments.Furthermore, no signiﬁ cant diﬀerences between treatments were found in energy-corrected milk, milk fatproduction, or body weight change. Milk protein production was, however, signiﬁcantly higher in group PROD.In early lactation, no diﬀerence in milking frequency was observed between treatments while for cows in mid- tolate lactation, milking frequency was signiﬁcantly higher in group EX than group PROD. Over the entire ex-periment, group EX cows spent signiﬁcantly less time outdoors than group PROD. In conclusion, oﬀering highyielding dairy cows in automatic milking systems high-quality pasture at a high allowance for a few hours inmorning and afternoon appears to be an interesting alternative to exercise paddock with full indoor feeding, as itcan reduce costs for supplementary silage, facilitate natural behaviour, and encourage cows to spend more timeoutdoors, while maintaining milk production at a level comparable to that of full indoor feeding.
Vitenskapelig – Chlorophyll a Fluorescence and Freezing Tests as Selection Methods for Growth Cessation and Increased Winter Survival in ×Festulolium
Liv Østrem, Marcin Rapacz, Arild Larsen, ...
In a ×Festulolium population (FuRs0357) of parental origin Lolium perenne × Festuca pratensis, selection of freezing tolerance by freezing tests on whole plants (FT) and chlorophyll a (Chl-a) fluorimetry on frozen detached leaves (CF) was assessed in high and low directions during two cycles of selection. The original population went through two cycles of random mating. All selections and non-selected intercrossed generations of the original population were established in field trials at a coastal site and a continental site in Norway. At the coastal site, analyses of Chl-a fluorimetry parameters and leaf growth on individual plants in autumn and winter hardiness observed in field plots in spring showed that the first-generation selections for high freezing tolerance were associated with winter hardiness and early growth cessation. The second-generation FT-selections for high freezing tolerance were also associated with winter hardiness, whereas the CF-high selections diverged toward high photosynthetic activity. Both low selections were correlated with high photosynthetic activity. There were smaller variations between generations in unselected generations of the original population. Low accumulated leaf growth and early growth cessation were observed in the secondgeneration FT-selection for high freezing tolerance, whereas high normalized difference vegetation index (NDVI) were seen in Chl-a selections. Both selection methods distinguished diverging selections with significantly different high and low freezing tolerance, but selection efficiency was comparable only for the first selection cycle. Moreover, due to mixed ploidy level in the original population, selection by FT and CF generated diploid and tetraploid plants, respectively, which intensified the response of selection, particularly in the diploid selections. Total dry matter yield (DMY) (mean of three annual cuts for 3 years) of the FT-high selections was lower than for the CF-selections. At coastal sites, selection intensity using freezing tests on whole plants should be adapted to actual climate conditions, to obtain genotypes that balance photosynthetic activity during autumn and good winter hardiness, making them persistent and high yielding.
Vitenskapelig – Assessments of Composite and Discrete Sampling Approaches for Water Quality Monitoring
Rachel Cassidy, Philip Jordan, Marianne Bechmann, ...
Achieving an operational compromise between spatial coverage and temporal resolution in national scale river water quality monitoring is a major challenge for regulatory authorities, particularly where chemical concentrations are hydrologically dependent. The efficacy of flow-weighted composite sampling (FWCS) approaches for total phosphorus (TP) sampling (n = 26–52 analysed samples per year), previously applied in monitoring programmes in Norway, Sweden and Denmark, and which account for low to high flow discharges, was assessed by repeated simulated sampling on high resolution TP data. These data were collected in three research catchments in Ireland over the period 2010–13 covering a base-flow index range of 0.38 to 0.69. Comparisons of load estimates were also made with discrete (set time interval) daily and sub-daily sampling approaches (n = 365 to >1200 analysed samples per year). For all years and all sites a proxy of the Norwegian sampling approach, which is based on re-forecasting discharge for each 2-week deployment, proved most stable (median TP load estimates of 87–98%). Danish and Swedish approaches, using long-term flow records to set a flow constant, were only slightly less effective (median load estimates of 64–102% and 80–96%, respectively). Though TP load estimates over repeated iterations were more accurate using the discrete approaches, particularly the 24/7 approach (one sample every 7 h in a 24 bottle sampler - median % load estimates of 93–100%), composite load estimates were more stable, due to the integration of multiple small samples (n = 100–588) over a deployment.
Vitenskapelig – The concentration-discharge slope as a tool for water quality management
Magdalena Z. Bieroza, A. Louise Heathwaite, Marianne Bechmann, ...
Recent technological breakthroughs of optical sensors and analysers have enabled matching the water quality measurement interval to the time scales of stream flow changes and led to an improved understanding of spatially and temporally heterogeneous sources and delivery pathways for many solutes and particulates. This new ability to match the chemograph with the hydrograph has promoted renewed interest in the concentration-discharge (c-q) relationship and its value in characterizing catchment storage, time lags and legacy effects for both weathering products and anthropogenic pollutants. In this paper we evaluated the stream c-q relationships for a number of water quality determinands (phosphorus, suspended sediments, nitrogen) in intensively managed agricultural catchments based on both high-frequency (sub-hourly) and long-term low-frequency (fortnightly-monthly) routine monitoring data. We used resampled high-frequency data to test the uncertainty in water quality parameters (e.g. mean, 95th percentile and load) derived from low-frequency sub-datasets. We showed that the uncertainty in water quality parameters increases with reduced sampling frequency as a function of the c-q slope. We also showed that different sources and delivery pathways control c-q relationship for different solutes and particulates. Secondly, we evaluated the variation in c-q slopes derived from the long-term low-frequency data for different determinands and catchments and showed strong chemostatic behaviour for phosphorus and nitrogen due to saturation and agricultural legacy effects. The c-q slope analysis can provide an effective tool to evaluate the current monitoring networks and the effectiveness of water management interventions. This research highlights how improved understanding of solute and particulate dynamics obtained with optical sensors and analysers can be used to understand patterns in long-term water quality time series, reduce the uncertainty in the monitoring data and to manage eutrophication in agricultural catchments.
Vitenskapelig – Integrated climate-chemical indicators of diffuse pollution from land to water
Per-Erik Mellander, Philip Jordan, Marianne Bechmann, ...
Management of agricultural diffuse pollution to water remains a challenge and is influenced by the complex interactions of rainfall-runoff pathways, soil and nutrient management, agricultural landscape heterogeneity and biogeochemical cycling in receiving water bodies. Amplified cycles of weather can also influence nutrient loss to water although they are less considered in policy reviews. Here, we present the development of climate-chemical indicators of diffuse pollution in highly monitored catchments in Western Europe. Specifically, we investigated the influences and relationships between weather processes amplified by the North Atlantic Oscillation during a sharp upward trend (2010– 2016) and the patterns of diffuse nitrate and phosphorus pollution in rivers. On an annual scale, we found correlations between local catchment-scale nutrient concentrations in rivers and the influence of larger, oceanic-scale climate patterns defined by the intensity of the North Atlantic Oscillation. These influences were catchment-specific showing positive, negative or no correlation according to a typology. Upward trends in these decadal oscillations may override positive benefits of local management in some years or indicate greater benefits in other years. Developing integrated climatechemical indicators into catchment monitoring indicators will provide a new and important contribution to water quality management objectives.
Vitenskapelig – Understanding Yield Loss and Pathogen Biology to Improve Disease Management: Septoria Nodorum Blotch - A Case Study in Wheat
Andrea Ficke, Christina Cowger, Gary Bergstrom, ...
The estimated potential yield losses caused by plant pathogens is up to 16% globally (Oerke 2006) and most research in plant pathology aims to reduce yield loss in our crops directly or indirectly. Yield losses caused by a certain disease depend not only on disease severity, but also on the weather factors, the pathogen’s aggressiveness, and the ability of the crop to compensate for reduced photosynthetic area. The yield loss-disease relationship in a certain host-pathogen system might therefore change from year to year, making predictions for yield loss very difficult at the regional or even at the farmer’s level. However, estimating yield losses is essential to determine disease management thresholds at which acute control measures such as fungicide applications, or strategic measures such as crop rotation or use of resistant cultivars are economically and environmentally sensible. Legislation in many countries enforces implementation of integrated pest management (IPM), based on economic thresholds at which the costs due to a disease justify the costs for its management. Without a better understanding of the relationship between disease epidemiology and yield loss, we remain insufficiently equipped to design adequate IPM strategies that will be widely adapted in agriculture. Crop loss studies are resource demanding and difficult to interpret for one particular disease, as crops are usually not invaded by only one pest or pathogen at a time. Combining our knowledge on disease epidemiology, crop physiology, yield development, damage mechanisms involved, and the effect of management practices can help us to increase our understanding of the disease-crop loss relationship. The main aim of this paper is to review and analyze the literature on a representative host-pathogen relationship in an important staple food crop to identify knowledge gaps and research areas to better assess yield loss and design management strategies based on economic thresholds. Wheat is one of the most important staple foods worldwide and is susceptible to several important plant diseases. In our article, we focus on Septoria nodorum blotch (SNB) or Glume blotch of wheat as an example for a stubble-borne, seed-transmitted disease with a worldwide distribution causing considerable and regular yield losses. In their review on yield losses due to wheat pathogens in Australia, Murray and Brennan (2009) estimated the current annual economic loss due to SNB as high as $108 × 106, with potential costs as high as $230 × 106. The causal fungus, Parastagonospora nodorum, is currently serving as a model organism for molecular studies of the intimate relationship between necrotic effector-producing fungal strains and their corresponding susceptibility genes present in wheat cultivars (Oliver et al. 2012). In this paper, we analyze the literature on the biology of this common wheat pathogen, the yield loss it reportedly has caused, and the effect of control strategies to reduce this loss. Based on this analysis, we will evaluate the use of common management practices to reduce disease-related yield loss and identify related research needs.
Vitenskapelig – The implementation of European Union (EU) rules on cross-border care: moving towards convergence?
Zuzana Nordeng, Frode Veggeland
This article studies the implementation of the European Union (EU)’s Patients’ Rights Directive in Germany and Norway. The objective of the Directive was to allow EU member states to have a say in the regulatory work, ensure predictability and uniformity in the application of EU rules on cross-border care, and enhance a move towards EU harmonisation in this area. So far, the implementation processes in Norway and Germany have mixed results regarding the likelihood of achieving uniformity and harmonisation. Although the Directive has had convergent effects on certain areas of cross-border care, such as setting up National Contact Points and providing patients with the basic right to treatment abroad, implementation also shows divergent patterns. In both countries, adapting to EU rules has strengthened patients’ rights to choose freely among health-service providers in a wider European healthservice market. However, due to legal discretion and country-specific institutions within which the new rules are applied, divergent patterns prevail.
Vitenskapelig – Evolution of the biosynthesis of two hydroxyacetophenones in plants
Geneviève J. Parent, Isabelle Giguère, Melissa Magerøy, ...
Acetophenones are phenolic metabolites of plant species. A metabolic route for the biosynthesis and release of 2 defence‐related hydroxyacetophenones in white spruce (Picea glauca) was recently proposed to involve 3 phases: (a) biosynthesis of the acetophenone aglycons catalysed by a currently unknown set of enzymes, (b) formation and accumulation of the corresponding glycosides catalysed by a glucosyltransferase, and (c) release of the aglycons catalysed by a glucosylhydrolase (PgβGLU‐1). We tested if this biosynthetic model is conserved across Pinaceae and land plant species. We assayed and surveyed the literature and sequence databases for possible patterns of the presence of the acetophenone aglycons piceol and pungenol and their glucosides, as well as sequences and expression of Pgβglu‐1 orthologues. In the Pinaceae, the 3 phases of the biosynthetic model are present and differences in expression of Pgβglu‐1 gene orthologues explain some of the interspecific variation in hydroxyacetophenones. The phylogenetic signal in the metabolite phenotypes was low across species of 6 plant divisions. Putative orthologues of PgβGLU‐1 do not form a monophyletic group in species producing hydroxyacetophenones. The biosynthetic model for acetophenones appears to be conserved across Pinaceae, whereas convergent evolution has led to the production of acetophenone glucosides across land plants.
Vitenskapelig – Long‐term vegetation changes of treeless heath communities in northern Fennoscandia: Links to climate change trends and reindeer grazing
Tuija Maliniemi, Jutta Kapfer, Patrick Saccone, ...
Question In recent decades, high‐latitude climate has shown regionally variable trends towards warmer and moister conditions. These changes have been predicted to cause afforestation or shrubification of open tundra, increases of warmth‐demanding southern species and plant groups favoured by increased moisture, and decline of species and habitats that are dependent on snow cover. In this study, we explore temporal changes in northern tundra upland plant communities along regional gradients and in local habitats. We ask how vegetation changes are linked with long‐term trends in regional climate and grazing pressure. Location Northern Europe. Methods In 2013–2014, we resurveyed a total of 108 vegetation plots on wind‐exposed and snow‐protected tundra habitats in three subareas along a bioclimatic gradient from the northern boreal to the arctic zone. Vegetation plots were originally sampled in 1964–1967. We related observed vegetation changes to changes in temperature, precipitation and grazing pressure, which all showed regionally variable increases over the study period. Results We found a significant increase of the evergreen dwarf shrub Empetrum nigrum subsp. hermaphroditum in snow‐protected communities and a prominent decrease of lichens throughout the study area. No evidence for extensive tree or larger shrub (Betula spp., Salix spp. or Juniperus communis) encroachment despite climatic warming trends was found. Among studied communities, most pronounced changes in vegetation were observed in snow‐protected boreal heaths on small isolated uplands, where community composition showed low resemblance to the original composition described decades ago. Changes in plant communities correlated with changes in summer and winter temperatures, summer precipitation and reindeer grazing pressure, yet correlations varied depending on region and habitat. Conclusions Northern tundra uplands vary in their resistance to on‐going climate change and reindeer grazing. Isolated treeless heaths of boreal forest–tundra ecotone appear least resistant to climate change and have already shifted towards new community states.
Vitenskapelig – The Svalbard Global Seed Vault and the ongoing 100 years seed storage experiment
Guro Brodal, Åsmund Asdal
The Svalbard Global Seed Vault was opened in 2008. The aim was to secure genetic diversity of crop plants important to future food production. The Seed Vault has the capacity to store 4.5 million seed samples, each containing on average 500 seeds sealed in airtight aluminum bags. By the end of 2016, the Vault had approximately 880,000 accessions representing more than 5000 plant species. The samples, originating from 71 gene banks and research institutes from all across the world, include major food crops such as wheat, rice, barley, sorghum, maize, legumes and forage crops, and vegetables. The seed samples are duplicates (backups) of seed stored in national, regional and international gene banks. Deposits can only be made by following a depositor agreement and the seed samples in the Vault remain the property of the depositing gene bank. The Vault is situated in permafrost at -3 to -4°C, but artificial cooling maintains a temperature of -18°C inside the Vault. Management of the Vault is secured through an agreement between the Norwegian Ministry of Agriculture and Food, the Crop Trust and the Nordic Genetic Resource Centre (NordGen). Secure storage of gene bank seeds in Svalbard was initiated during the 1980s, when the Nordic Gene Bank placed a collection of seed duplicates in an abandoned coal mine outside Longyearbyen in Svalbard. In addition to the secure storage of the base collection, a study of the longevity (germination and seed health) in long-term storage (100 years) in permafrost was started in 1986. A total of 42 seed samples of 16 common agricultural and horticultural Nordic species were included in the study. A set of sub-samples has been taken out for analyses every two and a half years during the first 20 years, and are taken out every five years for the next 80 years.
Vitenskapelig – Effects of repeated fertilization in young Norway spruce forests
Kjersti Holt Hanssen, Harald Kvaalen
Several studies have shown the positive effect of nitrogen fertilization on conifer growth. In young Norway spruce (Picea abies) stands, an additional effect of including a mixture of other nutrients has often, but not always, been found. We studied effects of repeated fertilization in 28 stands with young Norway spruce in central Norway. The treatments consisted of plots without nutrient addition (Control), fertilization with 150 kg N ha−1 (150 N), and fertilization with 150 kg N plus addition of P, K, Mg, B, Mn and Cu (150 N + mix), repeated three times with approximately eight years interval. There was a clear positive effect on volume increment of the 150 N and 150 N + mix treatments compared to Control, and the effect was significantly higher for 150 N + mix than for 150 N. Fertilization had a stronger effect in the first fertilization period than in the second, while the third period was intermediate. The effect of 150 N + mix was strongest at plots > 300 m a.s.l. However, this correlation may be due to geological conditions rather than elevation. Further studies are needed to find out under which edaphic conditions a nutrient mixture will increase growth substantially in young spruce stands.
Vitenskapelig – Enhancing water productivity using alternative rice growing practices: a case study from Southern India
Johannes Deelstra, Udaya Sekhar Nagothu, Krishna R. Kakumanu, ...
Saving water in irrigated agriculture is a high priority in areas with scarce water resources and impacted by climate change. This paper presents results of measurements on water Productivity (WP) under alternative rice growing practices such as alternating wetting and drying,direct seeded rice, modified systems of rice intensification and conventional paddy rice (NI)in two selected districts (Guntur in Andhra Pradesh and Nalgonda in Telangana, India). Under alternative practices, the yields varied from 5.72 to 6.11 t/ha compared with 4.71 t/ha under paddy rice. The average water application varied from 991 to 1494 mm under alternative practices while average application in conventional paddy rice was 2242 mm. Higher yield and lower water application led to an increase in WP varying from 0.45 to 0.59 kg/m3 under alternative practices compared with 0.22 kg/m3 under conventional paddy rice. The measurements showed that less water can be used to produce more crop under alternative rice growing practices. The results are important for water-scarce areas, providing useful information to policy makers, farmers, agricultural departments and water management boards in devising future climate-smart adaptation and mitigation strategies.
Vitenskapelig – Observer and relocation errors matter in resurveys of historical vegetation plots
Kris Verheyen, Martin Bažány, Ewa Chećko, ...
Aim: Revisits of non-permanent, relocatable plots first surveyed several decades ago offer a direct way to observe vegetation change and form a unique and increasingly used source of information for global change research. Despite the important insights that can be obtained from resurveying these quasi-permanent vegetation plots, their use is prone to both observer and relocation errors. Studying the combined effects of both error types is important since they will play out together in practice and it is yet unknown to what extent observed vegetation changes are influenced by these errors. Methods: We designed a study that mimicked all steps in a resurvey study and that allowed determination of the magnitude of observer errors only vs the joint observer and relocation errors. Communities of vascular plants growing in the understorey of temperate forests were selected as study system. Ten regions in Europe were covered to explore generality across contexts and 50 observers were involved, which deliberately differed in their experience in making vegetation records. Results: The mean geographic distance between plots in the observer+relocation error data set was 24 m. The mean relative difference in species richness in the observer error and the observer+relocation data set was 15% and 21%, respectively. The mean “pseudo-turnover” between the five records at a quasi-permanent plot location was on average 0.21 and 0.35 for the observer error and observer+relocation error data sets, respectively. More detailed analyses of the compositional variation showed that the nestedness and turnover components were of equal importance in the observer data set, whereas turnover was much more important than nestedness in the observer+relocation data set. Interestingly, the differences between the observer and the observer+relocation data sets largely disappeared when looking at temporal change: both the changes in species richness and species composition over time were very similar in these data sets. Conclusions: Our results demonstrate that observer and relocation errors are nonnegligible when resurveying quasi-permanent plots. A careful interpretation of the results of resurvey studies is warranted, especially when changes are assessed based on a low number of plots. We conclude by listing measures that should be taken to maximally increase the precision and the strength of the inferences drawn from vegetation resurveys.
Vitenskapelig – A comparison of the environmental impacts of different categories of insulation materials
Callum Aidan Stephen Hill, Andrew Norton, Janka Dibdiakova
More than sixty environmental product declarations of insulation materials (glass wool, mineral wool, expanded polystyrene, extruded polystyrene, polyurethane, foam glass and cellulose) have been examined and the published information for global warming potential (GWP) and for embodied energy (EE) has been analysed and is presented. A peer-review literature survey of the data for GWP and EE associated with the different insulation products is also included. The data for GWP (kg carbon dioxide equivalents) and EE (megajoules) is reported in terms of product mass or as a functional unit (FU) (1 m2 of insulation with R = 1 m2 K/W). Data for some classes of insulation material (such as glass wool) exhibit a relatively narrow range of values when reported in terms of weight of product or as a functional unit. Other classes of insulation material exhibit much wider distributions of values (e.g., expanded polystyrene). When reported per weight of product, the hydrocarbon-based insulation materials exhibit higher GWP and EE values compared to inorganic or cellulosic equivalents. However, when compared on an FU basis this distinction is no longer apparent and some of the cellulosic based materials (obtained by refining of wood chips) show some of the highest EE values. The relationship between the EE and GWP per kg of insulation product has also been determined as being 15.8 MJ per kg CO2 equivalents.
Vitenskapelig – Tool-box for effective renewable energy planning
Matthias Buchecker, Sebastian Eiter, Dina Stober, ...
Det er ikke registrert sammendrag
Vitenskapelig – Participatory planning of renewable energy with a focus on best practice
Dina Stober, Matthias Buchecker, Berthe Jongejan, ...
Det er ikke registrert sammendrag
Vitenskapelig – Public acceptance of renewable energy projects: a focus on wind energy
Monika Suškevičs, Matthias Buchecker, Sebastian Eiter, ...
Det er ikke registrert sammendrag
Det er ikke registrert sammendrag
Vitenskapelig – Nutrient release capability in Nordic and Baltic forest soils determined by dilute nitric acid extraction – Relationships with indicators for soil quality, pH and sustainable forest management
Ingeborg Callesen, Nicholas Clarke, Andis Lazdinš, ...
The long-term carrying capacity for biomass production is highly dependent on available soil resources. A soil test method for potential nutrient release capability was applied to 23 Nordic and Baltic forest soil profiles. The soils had coarse (10), medium (12) and fine (1) soil texture and most were podsolising. Extraction with dilute (0.1 M, 1:50 sample:solution ratio) nitric acid for 2 h was followed by 48 h and 168 h of extraction in soil samples from pedogenetic horizons. Dilute nitric acid solution was replaced after each step and release of mineral nutrient elements in solution was determined. C-horizon nutrient release (µmol g−1 fine earth, 0–218 h) was negatively correlated with mean annual temperature (MAT 0.5–8.5 °C) and for potassium (K) also mean annual precipitation (MAP 523–1440 mm y−1) suggesting a gradient in the mineralogy of the parent material that sediment transports during Pleistocene glaciations have not distorted. In B-horizons of sandy parent materials with felsic mineralogy cumulative nutrient release was positively correlated with pH and with Al and Fe release suggesting accumulation and stabilisation of nutrients in pedogenic products. E-horizons had less nutrient release capability than C-horizons, indicating a more weathered state of E-horizon parent material. Soil formation due to mineral dissolution and leaching of base cations and the gradient in parent material origin and weathering state both affected the observed pattern of nutrient release. On soils with very low mineral P resources (e.g. < 250 kg P ha−1 to 50 cm) by repeated dilute acid extraction, harvest of nutrient rich biomass will not be sustainable. However, it can’t be concluded that sites with high P availability by 0.1 M HNO3 can support an intensive harvest without compensation of P (and Ca) by fertilisation. Due to buffering of removed base cations in B-horizons, nutrient export with biomass may not be traceable as pH decline at decadal time scale. Therefore, the direct measurement of nutrient stocks by the extraction procedure (or other similar assessment of nutrient reserves by strong acid) is suggested as indicative for the mineral weathering capability of forest soils to recover from P and base cation depletion by biomass harvest.
Vitenskapelig – The relationships between biodiversity and ecosystem services and the effects of grazing cessation in semi-natural grasslands
Sølvi Wehn, Knut Anders Hovstad, Line Johansen
Land use change can affect biodiversity, and this has an impact on ecosystem services (ESs), but the relationships between biodiversity and ESs are complex and poorly understood. Biodiversity is declining due to the abandonment of extensively grazed semi-natural grasslands. We therefore aim to explore relationships between biodiversity and ESs provided by extensively managed semi-natural grasslands. Focusing on vascular plant species richness, as well as the ESs fodder quantity, quality, and stability, allergy control, climate regulation, nutrient cycling, pollination, and aesthetic appreciation, we carried out botanical field surveys of 28 paired extensively grazed and abandoned semi-natural grassland plots, with four subplots of 4m2 in each plot. The management of the semi-natural grasslands is and has been at low intensity. We calculated the influence of abandonment on the ES indicators, measured the correlation between the biodiversity measure of vascular plant species richness and ES indicators, and finally determined how the relationships between plant species richness and the ES indicators were affected by the cessation of the extensive management. ES indicators are often, but not always, positively correlated with species richness. Cessation of extensive grazing has both negative and positive effects on ES indicators but the relationships between species richness and ES indicators are often different in extensively managed and abandoned semi-natural grasslands. The relationships between species richness and ES indicators are less pronounced in the extensively managed semi-natural grassland than for the abandoned. One possible reason for this outcome is high functional redundancy in the extensively managed semi-natural grasslands.
Vitenskapelig – High-pruning of European beech (Fagus sylvatica L.) and pedunculate oak (Quercus robur L.): work efficiency for target pruning as a function of tree species, pruning height, branch characteristics, pole saw type and operator
Jens Peter Skovsgaard, Jacob Johan Mohr Markmann, Giulia Attocchi, ...
The objective of this study was to establish an operational model of productive work time per tree (work efficiency) for high-pruning of young European beech and pedunculate oak depending on tree species, pruning height, branch characteristics, pole saw type and operator. The final model included all of these independent variables with branch characteristics specified in terms of number of live branches and cross-sectional area of the thickest branch at the cut. Work time increased with increasing values of each of the three numeric variables. For a given pruning height the size of the largest branch was for all practical purposes more influential than the number of live branches. Beech took 28% longer to prune than oak. The German Ergo-Schnitt saw was 21% slower than the Japanese Silky Hayauchi saw. The variation in worker performance within our study was larger than that attributed to tree species and pruning equipment.
Vitenskapelig – Robotic in-row weed control in vegetables
Trygve Utstumo, Frode Urdal, Anders Brevik, ...
Vegetables and other row-crops represent a large share of the agricultural production. There is a large variation in crop species, and a limited availability in specialized herbicides. The robot presented here utilizes systematic growing techniques to navigate and operate in the field. By the use of machine vision it separates seeded vegetable crops from weed. Each weed within the row is treated with individual herbicide droplets, without affecting the crop. This results in a significant reduction in herbicide use, and allows for the use of herbicides that would otherwise harm the crop. The robot is tailored to this purpose with cost, maintainability, efficient operation and robustness in mind. The three-wheeled design is unconventional, and the design maintains maneuverability and stability with the benefit of reduced weight, complexity and cost. Indoor pot trials with four weed species demonstrated that the Drop-on-Demand system (DoD) could control the weeds with as little as 7.6 μg glyphosate or 0.15 μg iodosulfuron per plant. The results also highlight the importance of liquid characteristics for droplet stability and leaf retention properties. The common herbicide glyphosate had no effect unless mixed with suitable additives. A field trial with the robot was performed in a carrot field, and all the weeds were effectively controlled with the DoD system applying 5.3 μg of glyphosate per droplet. The robot and DoD system represent a paradigm shift to the environmental impact and health risks of weed control, while providing a valuable tool to the producers.
Vitenskapelig – Combining Hector SLAM and Artificial Potential Field for Autonomous Navigation Inside a Greenhouse
El Houssein Chouaib Harik, Audun Korsæth
The key factor for autonomous navigation is efficient perception of the surroundings,while being able to move safely from an initial to a final point. We deal in this paper with a wheeled mobile robot working in a GPS-denied environment typical for a greenhouse. The Hector Simultaneous Localization and Mapping (SLAM) approach is used in order to estimate the robots’ pose using a LIght Detection And Ranging (LIDAR) sensor. Waypoint following and obstacle avoidance are ensured by means of a new artificial potential field (APF) controller presented in this paper. The combination of the Hector SLAMand the APF controller allows themobile robot to performperiodic tasks that require autonomous navigation between predefined waypoints. It also provides themobile robot with a robustness to changing conditions thatmay occur inside the greenhouse, caused by the dynamic of plant development through the season. In this study, we show that the robot is safe to operate autonomously with a human presence, and that in contrast to classical odometrymethods, no calibration is needed for repositioning the robot over repetitive runs. We include here both hardware and software descriptions, as well as simulation and experimental results.
Vitenskapelig – Feeding frequency influences process performance and microbial community composition in anaerobic digesters treating steam exploded food waste
Kine Svensson, Lisa Paruch, John Christian Gaby, ...
In anaerobic digestion, studies of feeding frequency have produced conflicting results. Hence, the effect of feeding frequency on process variables and microbial community structure was investigated by comparing a laboratory-scale digester fed steam exploded food waste 10 times daily vs. one fed an equivalent amount once daily. The Frequently Fed Digester (FFD) produced on average 20% more methane and had lower effluent concentrations of long-chain fatty acids. Greater daily fluctuations in acetate, pH and biogas production rate could explain the lower specific methane yield and β-oxidation. Feeding frequency also influenced the microbial community whereby Tenericutes (42%) dominated in FFD but Firmicutes (31%) was most abundant in the Daily Fed Digester (DFD). Feeding frequency effects are therefore postulated to occur more often in digesters fed labile feedstocks at high organic loading rates.
Vitenskapelig – Oral administration of a chimeric Hepatitis B Virus S/preS1 antigen produced in lettuce triggers infection neutralizing antibodies in mice
Mihaela-Olivia Dobrica, Catalin Lazar, Lisa Paruch, ...
Hepatitis B Virus (HBV) infection can be prevented by vaccination. Vaccines containing the small (S)envelope protein are currently used in universal vaccination programs and achieve protective immuneresponse in more than 90% of recipients. However, new vaccination strategies are necessary for successfulimmunization of the remaining non- or low-responders. We have previously characterized a novel HBVchimeric antigen, which combines neutralization epitopes of the S and the preS1 domain of the large (L)envelope protein (genotype D). The S/preS121–47chimera produced in mammalian cells and Nicotianabenthamiana plants, induced a signiﬁcantly stronger immune response in parenterally vaccinated micethan the S protein. Here we describe the transient expression of the S/preS121–47antigen in an edibleplant, Lactuca sativa, for potential development of an oral HBV vaccine. Our study shows that oral admin-istration of adjuvant-free Lactuca sativa expressing the S/preS121–47antigen, three times, at 1lg/dose,was sufﬁcient to trigger a humoral immune response in mice. Importantly, the elicited antibodies wereable to neutralize HBV infection in an NTCP-expressing infection system (HepG2-NTCP cell line) moreefﬁciently than those induced by mice fed on Lactuca sativa expressing the S protein. These results sup-port the S/preS121–47antigen as a promising candidate for future development as an edible HBV vaccine.
Vitenskapelig – Long-term changes (1990–2015) in the atmospheric deposition and runoff water chemistry of sulphate, inorganic nitrogen and acidity for forested catchments in Europe in relation to changes in emissions and hydrometeorological conditions
Jussi Vuorenmaa, Algirdas Augustaitis, Burkhard Beudert, ...
The international Long-Term Ecological Research Network (ILTER) encompasses hundreds of long-term research/monitoring sites located in a wide array of ecosystems that can help us understand environmental change across the globe. We evaluated long-term trends (1990–2015) for bulk deposition, throughfall and runoff water chemistry and fluxes, and climatic variables in 25 forested catchments in Europe belonging to the UNECE International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems (ICP IM). Many of the IM sites form part of the monitoring infrastructures of this larger ILTER network. Trends were evaluated for monthly concentrations of non-marine (anthropogenic fraction, denoted as x) sulphate (xSO4) and base cations x(Ca + Mg), hydrogen ion (H+), inorganic N (NO3 and NH4) and ANC (Acid Neutralising Capacity) and their respective fluxes into and out of the catchments and for monthly precipitation, runoff and air temperature. A significant decrease of xSO4 deposition resulted in decreases in concentrations and fluxes of xSO4 in runoff, being significant at 90% and 60% of the sites, respectively. Bulk deposition of NO3 and NH4 decreased significantly at 60–80% (concentrations) and 40–60% (fluxes) of the sites. Concentrations and fluxes of NO3 in runoff decreased at 73% and 63% of the sites, respectively, and NO3 concentrations decreased significantly at 50% of the sites. Thus, the LTER/ICP IM network confirms the positive effects of the emission reductions in Europe. Air temperature increased significantly at 61% of the sites, while trends for precipitation and runoff were rarely significant. The site-specific variation of xSO4 concentrations in runoff was most strongly explained by deposition. Climatic variables and deposition explained the variation of inorganic N concentrations in runoff at single sites poorly, and as yet there are no clear signs of a consistent deposition-driven or climate-driven increase in inorganic N exports in the catchments.
Vitenskapelig – Cryotherapy: A Novel Method for Virus Eradication in Economically Important Plant Species
Min-Rui Wang, Long Chen, Zhibo Zhang, ...
Virus diseases have been a great threat to production of economically important crops. In practice, the use of virus-free planting material is an effective strategy to control viral diseases. Cryotherapy, developed based on cryopreservation, is a novel plant biotechnology tool for virus eradication. Comparing to the traditional meristem culture for virus elimination, cryotherapy resulted in high efficiency of pathogen eradication. In general, cryotherapy includes seven major steps: (1) introduction of infected plant materials into in vitro cultures, (2) shoot tip excision, (3) tolerance induction of explants to dehydration and subsequent freezing in liquid nitrogen (LN), (4) a short-time treatment of explants in LN, (5) warming and post-culture for regeneration, (6) re-establishment of regenerated plants in greenhouse conditions, and (7) virus indexing.
Vitenskapelig – Regional differences in technical efficiency and technological gap of the Norwegian dairy farms: a stochastic meta-frontier model
Habtamu Alem, Gudbrand Lien, J. Brian Hardaker, ...
This paper compares technical efficiencies (TEs) and technological gap ratios (TGRs) for dairy farms in regions of Norway, accounting for differences in working environments. We used the state-of-the-art stochastic meta-frontier approach to estimate TEs and TGRs to account for regional heterogeneity, and the ‘true’ random-effect model to account for farm effects. The dataset used was farm-level balanced panel data for 24 years (1992–2014), with 5442 observations from 731 dairy farms. The results of the analysis provide empirical evidence of small regional differences in TEs, TGRs, and input use. Furthermore, the results may provide support for the more regionally specific agricultural policy, in terms of support schemes and structural regulations.
Vitenskapelig – Material Characteristics and Requirements for Photobiological Hydrogen Production Applications
Vitenskapelig – Growth, microtuber production and physiological metabolism in virus-free and virus-infected potato in vitro plantlets grown under NaCl-induced salt stress
Jing-Wei Li, Hai-Yan Chen, Jiao Li, ...
Viral diseases (a biotic stress) and salinity (an abiotic stress) have been/are the two major constraints for sustainable development of the world’s agricultural production including potato. Crops grown in field are often exposed simultaneously to abiotic and biotic stress, and responses of plants to co-stress by two or more factors may differ from those to each of the multiple stresses. Using in vitro cultures, we demonstrated that virus infection (singly and in combination) or salt, and co-stress by virus infection (singly and in combination) and salt significantly reduced growth and microtuber production, and caused severely oxidative cell damage determined by levels of O2·− and methane dicarboxylic aldehyde, and H2O2 localization in situ. Alterations in physiological metabolism by increasing total soluble sugar and free proline, and by decreasing chlorophyll content are responses of potato plantlets to virus infection (singly and in combination) or salt stress and co-stress by virus infection (singly and in combination) and salt. Oxidative cell damage and reduced chlorophyll content caused by virus and/or salt are believed to be responsible for the reduced growth, eventually resulting in decreased tuber yield. Results reported here would help us to better understand possible mechanism of reduced tuber yield by virus infection and/or salt stress.
Vitenskapelig – Phototactic response of Frankliniella occidentalis to sticky traps with blue light emitting diodes in herb and Alstroemeria greenhouses
Nina Johansen, Torfinn Torp, Knut Asbjørn Solhaug
Blue and yellow sticky traps equipped with blue light emitting diodes (LEDs) were evaluated for their attractiveness to the western flower thrips (Frankliniella occidentalis Pergande) and compared to similar traps without light in two greenhouses with commercial production of either mixed herbs or Alstroemeria cut flowers. Blue traps were more attractive to F. occidentalis than the yellow traps in both crops, regardless of whether they were equipped with light or not. In herbs, the blue light equipped traps caught 1.7 to 2.5 times more thrips compared to blue traps without light, and 1.7 to 3.0 times more thrips than yellow traps with light. Blue light on both blue and yellow traps increased thrips catches in one out of two experiments in Alstroemeria. The blue light equipped traps caught 3.4 and 4.0 times more thrips than blue traps without light in coloured and white Alstroemeria cultivars, respectively, whereas yellow light equipped traps increased thrips catches 4.5 times compared to yellow traps without light in both coloured and white cultivars. The yellow light equipped traps caught, however, only equal to or only slightly more thrips than blue traps without light, and caught fewer thrips than the light equipped blue traps. The relative trapping efficiency of the different combinations of trap colour and light varied with experiment, crop and Alstroemeria cultivars. This suggests that factors other than merely the addition of light influenced the thrips' phototactic response to the traps. Such factors could be differences in the relative strength of the competition between attractive signals from traps and plants between the two crops and Alstroemeria cultivars, thrips density, seasonal lighting conditions or different pest management strategies and other operational procedures in the greenhouses. The light from the traps did not increase the thrips population on the plants below the traps. The implications of the results for thrips control and suggestions for further studies are discussed.
Vitenskapelig – Modeling the Influence of Eutrophication and Redox Conditions on Mercury Cycling at the Sediment-Water Interface in the Berre Lagoon
Svetlana Pakhomova, Evgeniy Yakushev, Elizaveta Protsenko, ...
This study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(0)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast subjected to seasonal anoxia. The first scenario represents the conditions in the lagoon that are compared with experimental data. The four other scenarios were produced by varying the biological productivity, using low and high nutrient (N and P) concentrations, and by varying the redox conditions using different intensity of vertical mixing in the water column. The results of the simulation show that both oxidized and reduced sediments can accumulate Hg, but any shifts in redox conditions in bottom water and upper sediment layer lead to the release of Hg species into the water column. Eutrophication and/or restricted vertical mixing lead to reducing conditions and intensify MeHg formation in the sediment with periodic release to the water column. Oxygenation of an anoxic water body can lead to the appearance of Hg species in the water column and uptake by organisms, whereby Hg may enter into the food web. The comparison of studied scenarios shows that a well-oxygenated eutrophic system favors the conditions for Hg species bioaccumulation with a potential adverse effect on the ecosystem. The research is relevant to the UN Minimata convention, EU policies on water, environmental quality standards and Mercury in particular.
Vitenskapelig – First Report of Pseudomonas syringae pv. syringae Causing Bacterial Blister Bark on Apple in Norway
Juliana Perminow, Jorunn Børve, May Bente Brurberg, ...
Vitenskapelig – First Report of Potato Cyst Nematode Globodera pallida Infecting Potato (Solanum tuberosum) in Kenya
Harrison Mburu, Laura Cortada, Grace Mwangi, ...
Vitenskapelig – The potential to use documentation in national Red Lists to characterize red-listed forest species in Fennoscandia and to guide conservation
Lise Tingstad, John-Arvid Grytnes, Vivian Astrup Felde, ...
Loss of biodiversity is a pressing global issue, hence it is vital to facilitate informed and effective conservation. As conservation mainly operates at the level of habitats, aiming for species of conservation interest, conservation and management require adequate ecological knowledge of prioritized species for the geographic and environmental setting considered. Our aim was to investigate if ecological documentation in national Red Lists could be combined and used to identify important forest habitats and ecological variables for red-listed forest species in Fennoscandia, and whether this knowledge could be arranged at different geographical scales and for various selections of species of conservation interest. We compiled the national Red Lists of Finland, Norway and Sweden and extracted ecological information for all red-listed forest species (n = 4830). We used a principal component analysis to investigate variation in distribution of species and their habitat associations and taxonomical groups, and to group species of similar associations. We further used the listed species in Sweden as an example, and compared the proportions of species associated to the ecological variables dead wood, living trees or merely the “forest floor and understory” a) at larger and smaller scale (Fennoscandia – county in Sweden), b) in regions with contrasting biomes (nemoral and boreal), and c) in two more limited selections of species of conservation interest; Fennoscandian and globally red-listed species also red-listed in Sweden. Ecological information could be extracted for 96% of the species, albeit with a low resolution; i.e. overall forest habitats, associated tree species, lifeforms and six other ecological variables selected based on their frequent appearance in the Red List documentation. Using this information, we identified five large-scale patterns for Fennoscandian red-listed species; the majority of red-listed species is associated with coniferous forest. The number of red-listed species associated with specific tree species was poorly correlated with the amount of each tree species in Fennoscandia. Dead wood was one of the most important habitat features in terms of number of associated red-listed species, and the proportion of species associated to dead wood was similar in coniferous, boreal and nemoral broadleaved forests types. We demonstrate that ecological documentation in national Red Lists can be used to identify general ecological variables at varying geographical scales and for different selections of species, albeit not with sufficient resolution to provide detailed local conservation guidelines.
Vitenskapelig – Subtle foodscape displacement of a native ungulate by free-ranging livestock in a forest agroecosystem
Hilde Karine Wam, Ivar Herfindal
The prevalence of livestock grazing in wildlife area s is increasing. This transformation of ecosys- tems into agroecosystems is concerning because the intr oduction of new species may cause niche displacement of the functionally related native species. We used a la rge-scale fence scheme and f ecal analyses to study the in fl uence of free-ranging livestock on moose diet on thr ee boreal forest ranges. We found low interspeci fi cdiet overlap between moose and livestock (mean Pianka ’ s O across ranges = 0.21, SD = 0.104), and the diet overlap with livestock did not differ between moose in areas with livestock and in adjacent control areas without live- stock. Still, moose sympatric with livestock had less fe cal nitrogen (a proxy for diet quality) than moose in the control areas. Our fi ndings suggest that interspeci fi c interactions other than direct food competition contributed to reduce the moose ’ foraging opportunities, such as altered forag e abundance and composition, or behavioral avoidance of livestock. We caution that displacement in the foodscape (i.e., spati otemporal use of food) can occur through pathways not evident in niche indices based on composition of plant species in the diet.
Vitenskapelig – Sedum root foraging in layered green roof substrates
Peng Ji, Arne Sæbø, Virginia Stovin, ...
Background and aims Layered profiles of designed soils may provide long-term benefits for green roofs, provided the vegetation can exploit resources in the different layers. We aimed to quantify Sedum root foraging for water and nutrients in designed soils of different texture and layering. Methods In a controlled pot experiment we quantified the root foraging ability of the species Sedum album (L.) and S. rupestre (L.) in response to substrate structure (fine, coarse, layered or mixed), vertical fertiliser placement (top or bottom half of pot) and watering (5, 10 or 20 mm week−1 ). Results Water availability was the main driver of plant growth, followed by substrate structure, while fertiliser placement only had marginal effects on plant growth. Root foraging ability was low to moderate, as also reflected in the low proportion of biomass allocated to roots (5–13%). Increased watering reduced the proportion of root length and root biomass in deeper layers. Conclusions Both S. album and S. rupestre had a low ability to exploit water and nutrients by precise root foraging in substrates of different texture and layering. Allocation of biomass to roots was low and showed limited flexibility even under water-deficient conditions.
Vitenskapelig – Adaptive differentiation among populations of the Mediterranean dry grassland species Brachypodium retusum: The role of soil conditions, grazing, and humidity
Christel Vidaller, Thierry Dutoit, Yosra Ibrahim, ...
PREMISE OF THE STUDY: Genetic differentiation in plant species may result from adaptation to environmental conditions, but also from stochastic processes. The drivers selecting for local adaptation and the contribution of adaptation to genetic differentiation are often unknown. Restoration and succession studies have revealed different colonization patterns for Brachypodium retusum, a common Mediterranean grass. In order to understand these patterns, we tested population differentiation and adaptation to different environmental factors. METHODS: Structured sampling of 12 populations from six sites and two soil types within site was used to analyze the spatial and environmental structure of population differentiation. Sampling sites differ in grazing intensity and climate. We tested germination and growth in a common garden. In subsets, we analyzed the differential response to stone cover, grazing and soil moisture. KEY RESULTS: We found significant differences among populations. The site explained population differentiation better than soil, suggesting a dominant influence of climate and/or genetic drift. Stone cover had a positive influence on seedling establishment, and populations showed a differential response. However, this response was not related to environmental differences between collection sites. Regrowth after clipping was higher in populations from the more intensively grazed Red Mediterranean soils suggesting an adaptation to grazing. Final germination was generally high even under drought, but germination response to differences in soil moisture was similar across populations. CONCLUSIONS: Adaptive population differentiation in germination and early growth may have contributed to different colonization patterns. Thus, the provenance of B. retusum needs to be carefully considered in ecological restoration.
Vitenskapelig – Variations in polyphenol and heavy metal contents of wild-harvested and cultivated seaweed bulk biomass: Health risk assessment and implication for food applications
Michael Roleda, Hélène Marfaing, Natasa Desnica, ...
Seaweeds are increasingly used in European cuisines due to their nutritional value. Many algal constituents, such as polyphenols, are important antioxidants and thus considered beneficial to humans. However, many seaweed species can accumulate heavy metals and exhibit potential health risks upon ingestion. We investigated temporal and spatial variations in polyphenol and heavy metal (As, Cd, Hg, Pb) concentrations of three edible seaweed species. The brown algae Saccharina latissima and Alaria esculenta, and the red alga Palmaria palmata were sourced from natural populations and aquaculture in the NE Atlantic and processed as bulk biomass mimicking industrial scales. The mean polyphenol content was species-specific (Alaria > Saccharina > Palmaria), and highest in winter (for Alaria and Saccharina) and spring (for Palmaria); inter-annual and spatial variations were marginal. Heavy metal concentrations varied between species and depended on collection site, but seasonal variations were minimal. Our data suggest that all three species are good sources of antioxidants, and the heavy metal concentrations are below the upper limits set by the French recommendation and the EU Commission Regulation on contaminants in foodstuffs. A health risk assessment indicated that consumption of these seaweed species poses a low risk for humans with regard to heavy metals. However, an EU-wide regulation on maximal concentration of heavy metals in seaweeds should be established.
Vitenskapelig – The role of precipitation, and petal and leaf infections in Sclerotinia stem rot of spring oilseed Brassica crops in Norway
Andrea Ficke, Chloé Grieu, May Bente Brurberg, ...
Sclerotinia stem rot (SSR) is the most important disease of oilseed Brassica crops in Norway. Fungicide applications should be aligned with the actual need for control, but the SSR prediction models used lack accuracy. We have studied the importance of precipitation, and the role of petal and leaf infection for SSR incidence by using data from Norwegian field and trap plant trials over several years. In the trials, SSR incidence ranged from 0 to 65%. Given an infection threshold of 25% SSR, regression and Receiver Operating Characteristics (ROC) analysis were used to evaluate different precipitation thresholds. The sum of precipitation two weeks before and during flowering appeared to be a poor predictor for SSR infection in our field and trap plant trials (P = 0.24, P = 0.11, respectively). Leaves from three levels (leaf one, three, five), and petals were collected at three to four different times during flowering from nine field sites over two years and tested for SSR infection with real-time PCR. Percentage total leaf and petal infection explained 57 and 45% of variation in SSR incidence, respectively. Examining the different leaves and petals separately, infection of leaf three sampled at full flowering showed the highest explanation of variation in later SSR incidence (R2 = 65%, P < 0.001). ROC analysis showed that given an infection threshold of 45%, both petal and leaf infection recommended spraying when spraying was actually needed. Combining information on petal and leaf infection during flowering with relevant microclimate factors in the canopy, instead of the sum of precipitation might improve prediction accuracy for SSR.
Vitenskapelig – Dieback of European Ash: What Can We Learn from the Microbial Community and Species-Specific Traits of Endophytic Fungi Associated with Ash?
Ari Hietala, Isabella Børja, Hugh Cross, ...
European ash (Fraxinus excelsior), a keystone species with wide distribution and habitat range in Europe, is threatened at a continental scale by an invasive alien ascomycete, Hymenoscyphus fraxineus. In its native range of Asia, this fungus is a leaf endophyte with weak parasitic capacity and robust saprobic competence in local ash species that are closely related to European ash. In European ash, H. fraxineus has a similar functional role as in Asia, but the fungus also aggressively kills shoots, resulting in crown dieback and tree death. H. fraxineus is a typical invasive species, as its spread relies on high propagule pressure. While crown dieback of European ash is the most obvious symptom of ash dieback, the annual colonization of ash leaves is a crucial key dependency for the invasiveness of H. fraxineus, since its fruiting bodies are formed on overwintered leaf vein tissues in soil debris. Leaves of European ash host a wide range of indigenous epiphytes, endophytes, facultative parasites and biotrophic fungi, including Hymenoscyphus albidus, a relative of H. fraxineus that competes for the same sporulation niche as the invader. At face value, leaves of European ash are colonized by a large and diverse indigenous mycobiome. In order to understand why this invader became successful in Europe, we discuss and summarize the current knowledge of diversity, seasonal dynamics and traits of H. fraxineus and indigenous fungi associated with leaves of European ash.
Vitenskapelig – Impact of weather cues and resource dynamics on mast occurrence in the main forest tree species in Europe
Anita Nussbaumer, Peter Waldner, Vladislav Apuhtin, ...
Mast seeding, the synchronised occurrence of large amounts of fruits and seeds at irregular intervals, is a reproductive strategy in many wind-pollinated species. Although a series of studies have investigated mast year (MY) patterns in European forest tree species at the regional scale, there are few recent evaluations at a European scale on the impact of weather variables (weather cues) and resource dynamics on mast behaviour. Thus the main objective of this study is to investigate the impact of specific weather conditions, as environmental drivers for MYs, on resources in Fagus sylvatica L., Quercus petraea (Matt.)Liebl., Quercus robur L., Picea abies (L.) Karst. and Pinus sylvestris L. at a European level and to explore the robustness of the relationships in smaller regions within Europe. Data on seed production originating from the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) were analysed. Three beta regression models were applied to investigate the impact of seasonal weather variables on MY occurrence, as well as the influence of fruiting intensity levels in the years prior to MYs. Resource dynamics are analysed at three different spatial scales (continent, countries and ecoregions). At a European scale, important weather cues for beech MYs were a cold and wet summer two years before a MY, a dry and warm summer one year before a MY and a warm spring in the MY. For spruce, a cold and dry summer two years prior to a MY and a warm and dry summer in the year before the MY showed the strongest associations with the MY. For oak, high spring temperature in the MY was the most important weather cue. For beech and spruce, and to some extent also for oak species, the best fitting models at European scale were well reflected by those found at smaller scales. For pine, best fitting models were highly diverse concerning weather cues. Fruiting levels were high in all species two years before the MY and also high one year before the MY in the oak species and in pine. In beech, fruiting levels one year before the MY were not important and in spruce, they were inconsistent depending on the region. As a consequence, evidence of resource depletion could only be seen in some regions for spruce.
Vitenskapelig – Faba bean cultivation - revealing novel managing practices for more sustainable and competitive European cropping systems
Anestis Karkanis, Georgia Ntatsi, Liga Lepse, ...
Faba beans are highly nutritious because of their high protein content: they are a good source of mineral nutrients, vitamins, and numerous bioactive compounds. Equally important is the contribution of faba bean in maintaining the sustainability of agricultural systems, as it is highly efficient in the symbiotic fixation of atmospheric nitrogen. This article provides an overview of factors influencing faba bean yield and quality, and addresses the main biotic and abiotic constraints. It also reviews the factors relating to the availability of genetic material and the agronomic features of faba bean production that contribute to high yield and the improvement of European cropping systems. Emphasis is to the importance of using new high-yielding cultivars that are characterized by a high protein content, low antinutritional compound content, and resistance to biotic and abiotic stresses. New cultivars should combine several of these characteristics if an increased and more stable production of faba bean in specific agroecological zones is to be achieved. Considering that climate change is also gradually affecting many European regions, it is imperative to breed elite cultivars that feature a higher abiotic–biotic stress resistance and nutritional value than currently used cultivars. Improved agronomical practices for faba bean crops, such as crop establishment and plant density, fertilization and irrigation regime, weed, pest and disease management, harvesting time, and harvesting practices are also addressed, since they play a crucial role in both the production and quality of faba bean.
Vitenskapelig – Recognition of candidate transcription factors related to bilberry fruit ripening by de novo transcriptome and qRT-PCR analyses
Nga Nguyen, Marko Suokas, Katja Karppinen, ...
Bilberry (Vaccinium myrtillus L.) fruits are an excellent natural resource for human diet because of their special favor, taste and nutritional value as well as medical properties. Bilberries are recognized for their high anthocyanin content and many of the genes involved in the anthocyanin biosynthesis have been characterized. So far, neither genomic nor RNA-seq data have been available for the species. In the present study, we de novo sequenced two bilberry fruit developmental stages, unripe green (G) and ripening (R). A total of 57,919 unigenes were assembled of which 80.2% were annotated against six public protein databases. The transcriptome served as exploratory data to identify putative transcription factors related to fruit ripening. Diferentially expressed genes (DEGs) between G and R stages were prominently upregulated in R stage with the functional annotation indicating their main roles in active metabolism and catalysis. The unigenes encoding putative ripening-related regulatory genes, including members of NAC, WRKY, LOB, ERF, ARF and ABI families, were analysed by qRTPCR at fve bilberry developmental stages. Our de novo transcriptome database contributes to the understanding of the regulatory network associated with the fruit ripening in bilberry and provides the frst dataset for wild Vaccinium species acquired by NGS technology.
Vitenskapelig – Contributors to faecal water contamination in urban environments
Lisa Paruch, Adam M. Paruch
Faecal contamination of water has both anthropogenic and zoogenic origins that can shade various point and nonpoint/diffuse sources of pollution. Due to the dual origin and number of sources of faecal contamination, there are immense challenges in the implementation of effective measures to protect water bodies from pollution that poses threats to human and environmental health. The main health threats refer to infections, illnesses and deaths caused by enteric pathogenicmicrobes, in particular those responsible for waterborne zoonoses. To detect and identify the origins and sources of faecal pollution simultaneously, various methods and indicators have been compiled into a comprehensivemeasuring toolbox. Molecular diagnostics using genetic markers derived from Bacteroidales 16S rRNA gene sequences are quite prevalent in the current methodological implementation for the identification of faecal contamination sources in water. For instance, a culture- and library-independent microbial source tracking toolbox combining micro- and molecular biology tests run as a three-step procedure has been implemented in Norway. Outcomes from the Norwegian studies have identified two general trends in dominance of contributors to faecal water contamination in urban environments. Firstly, there is a tendency of higher contributions from anthropogenic sources during the cold season. Secondly, the identification of the dominance of zoogenic sources in faecalwater contamination during warm periods of the year.
Vitenskapelig – Nonlinear dynamics of river runoff elucidated by horizontal visibility graphs
Holger Lange, Sebastian Sippel, Osvaldo A. Rosso
Horizontal Visibility Graphs (HVGs) are a recently developed method to construct networks from time series. The values of the time series are considered as the nodes of the network and are linked to each other if there is no larger value between them, such as they can “see” each other. The network properties reflect the nonlinear dynamics of the time series. For some classes of stochastic processes and for periodic time series, analytical results can be obtained for network-derived quantities such as the degree distribution, the local clustering coefficient distribution, the mean path length, and others. HVGs have the potential to discern between deterministic-chaotic and correlated-stochastic time series. Here, we investigate the sensitivity of the HVG methodology to properties and pre-processing of real-world data, i.e., time series length, the presence of ties, and deseasonalization, using a set of around 150 runoff time series from managed rivers at daily resolution from Brazil with an average length of 65 years. We show that an application of HVGs on real-world time series requires a careful consideration of data pre-processing steps and analysis methodology before robust results and interpretations can be obtained. For example, one recent analysis of the degree distribution of runoff records reported pronounced sub-exponential “long-tailed” behavior of North American rivers, whereas another study of South American rivers showed hyper-exponential “short-tailed” behavior resembling correlated noise.We demonstrate, using the dataset of Brazilian rivers, that these apparently contradictory results can be reconciled by minor differences in data-preprocessing (here: small differences in subtracting the seasonal cycle). Hence, data-preprocessing that is conventional in hydrology (“deseasonalization”) changes long-term correlations and the overall runoff dynamics substantially, and we present empirical consequences and extensive simulations to investigate these issues from a HVG methodological perspective. After carefully accounting for these methodological aspects, the HVG analysis reveals that the river runoff dataset shows indeed complex behavior that appears to stem from a superposition of short-term correlated noise and “long-tailed behaviour,” i.e., highly connected nodes. Moreover, the construction of a dam along a river tends to increase short-term correlations in runoff series. In summary, the present study illustrates the (often substantial) effects of methodological and data-preprocessing choices for the interpretation of river runoff dynamics in the HVG framework and its general applicability for real-world time series.
Vitenskapelig – Utilisation of chemically modified lampante oil for wood protection
Matthew Schwarzkopf, Michael Burnard, Viacheslav Tverezovskiy, ...
Within the Slovenian region of Istria, the olive growing and oil production industry is strong. This industry has a long history and the olives grown here have high levels of biologically active compounds including a variety of phenolic compounds. Using residual materials generated by this industry in potential wood protection systems would not only valorise low-value materials and stimulate rural economies but would also provide an alternative to currently used oil-based protection systems. The objective of this study was to produce an oil treatment for wood protection and assess its efficacy in reducing leaching, weathering effects, and fungal decay. Two maleinisation techniques were used to chemically modify low-value lampante oil in an attempt to limit leaching when impregnated in wood. Pinus sylvestris (Scots pine) and Fagus sylvatica (European beech) were treated with the modified oils and underwent leaching, accelerated weathering, and decay tests. Leaching of the treatment oils was relatively low compared with other experiments and beech wood specimens treated with a direct maleinisation treatment showed improvement in performance compared to control specimens. In addition, it was found that the modified oils were not completely removed from the wood after solvent extraction indicating that they could potentially be used as an immobilisation agent in combination with other treatments thereby reducing the amount of active component of the protective agent.
Vitenskapelig – A probability model for root and butt rot in Picea abies derived from Norwegian national forest inventory data
Gro Hylen, Aksel Granhus
Root rot in Norway spruce (Picea abies (L.) Karst.) causes substantial economic losses to the forestry sector. In this study, we developed a probability model for decay at breast height utilizing 18,141 increment cores sampled on temporary plots of the Norwegian National Forest Inventory. The final model showed a good fit to the data and retained significant relationships between decay and a suite of tree, stand and site variables, including diameter at breast height, stand age, altitude, growing season temperature sum (threshold 5°C), and vegetation type. By comparing model predictions with recorded decay at stump height in an independent data set, we estimated a proportionality function to adjust for the inherent underestimation of total rot that will be obtained by applying a probability model derived from increment cores sampled at breast height. We conclude that the developed model is appropriate for national and regional scenario analyses in Norway, and could also be useful as a tool for operational forestry planning. This would however require further testing on independent data, to assess how well the new model predicts decay at local scales.
Vitenskapelig – The relationship between phenological development of red clover and its feed quality in mixed swards
Shahid Nadeem, Håvard Steinshamn, Elin Halvorsen Sikkeland, ...
Det er ikke registrert sammendrag
Vitenskapelig – Longer growing season with warmer Autumn at Northern latitudes - can farmers take an extra cut?
Marit Jørgensen, Anne Kjersti Bakken, Tor Lunnan, ...
Det er ikke registrert sammendrag
Vitenskapelig – Transcriptome and metabolome analyses provide insights into root and root-released organic anion responses to phosphorus deficiency in oat
Yanliang Wang, Erik Lysøe, Tegan Armarego-Marriott, ...
Vitenskapelig – Propagule pressure build-up by the invasive Hymenoscyphus fraxineus following its introduction to an ash forest inhabited by the native Hymenoscyphus albidus
Ari Hietala, Isabella Børja, Halvor Solheim, ...
Dieback of European ash, caused by the ascomycete Hymenoscyphus fraxineus originating from Asia, has rapidly spread across Europe, and is threatening this keystone tree at a continental scale. High propagule pressure is characteristic to invasive species. Consistently, the enormous production of windborne ascospores by H. fraxineus in an ash forest with epidemic level of disease obviously facilitates its invasiveness and long distance spread. To understand the rate of build-up of propagule pressure by this pathogen following its local introduction, during 2011–2017 we monitored its sporulation at a newly infested ash stand in south-western Norway characterized with mild winters and cool summers. We also monitored the propagule pressure by Hymenoscyphus albidus, a non-pathogenic native species that competes for the same sporulation niche with H. fraxineus. During the monitoring period, crown condition of ash trees had impaired, and 20% of the dominant trees were severely damaged in 2017. H. fraxineus showed an exponential increase in spore production between 2012 and 2015, followed by drastic decline in 2016 and 2017. During 2011–2013, the two Hymenoscyphus species showed similar sporulation level, but thereafter spores of H. albidus were no longer detected. The data suggest that following local introduction, the population of H. fraxineus reaches rapidly an exponential growth stage if the local weather conditions are favorable for ascomata maturation across years. In the North Atlantic climate, summer temperatures critically influence the pathogen infection pressure, warm summers allowing the population to grow according to its biotic potential, whereas cold summers can cause a drastic decline in propagule pressure.
Vitenskapelig – Five decades of warming: impacts on snow cover in Norway
Jonathan Rizzi, Irene Brox Nilsen, James Howard Stagge, ...
Northern latitudes are experiencing faster warming than other regions in the world, which is partly explained by the snow albedo feedback. In Norway, mean temperatures have been increasing since the 1990s, with 2014 being the warmest year on record, 2.2 °C above normal (1961–1990). At the same time, a concurrent reduction in the land area covered by snow has been reported. In this study, we present a detailed spatial and temporal (monthly and seasonal) analysis of trends and changes in snow indices based on a high resolution (1 km) gridded hydro-meteorological dataset for Norway (seNorge). During the period 1961–2010, snow cover extent (SCE) was found to decrease, notably at the end of the snow season, with a corresponding decrease in snow water equivalent except at high elevations. SCE for all Norway decreased by more than 20,000 km2 (6% of the land area) between the periods 1961–1990 and 1981–2010, mainly north of 63° N. Overall, air temperature increased in all seasons, with the highest increase in spring (particularly in April) and winter. Mean monthly air temperatures were significantly correlated with the monthly SCE, suggesting a positive land–atmosphere feedback enhancing warming in winter and spring.
Vitenskapelig – Consumer cohorts and the demand for meat and dairy products
Geir Wæhler Gustavsen, Kyrre Rickertsen
Over their life course, people change their consumption habits when prices, income, tastes or nutritional needs change. The time period during which an individual grew up is often reflected in his or her consumption of different types of food. To investigate the possible links between demographic changes and food consumption, we constructed two-step censored demand systems for different groups of foods. We estimated the systems using Norwegian data for the 1986 – 2012 period. In the systems, age, period, cohort, other demographic and economic variables are included. The estimated systems are used to construct a long-run forecasting model for meat and dairy products. In this model, younger cohorts replace older cohorts with a different consumption pattern. The total purchases of beef, lamb, pork and fluid milk are predicted to decrease, while the total purchases of chicken, yoghurt and cheese are predicted to increase towards 2027.
Vitenskapelig – Elevational treeline and forest line dynamics in Norwegian mountain areas - a review
Anders Bryn, Kerstin Potthoff
Purpose Treelines and forest lines (TFLs) have received growing interest in recent decades, due to their potential role as indicators of climate change. However, the understanding of TFL dynamics is challenged by the complex interactions of factors that control TFLs. The review aims to provide an overview over the trends in the elevational dynamics of TFLs in Norway since the beginning of the 20th century, to identify main challenges to explain temporal and spatial patterns in TFL dynamics, and to identify important domains for future research. Method A systematic search was performed using international and Norwegian search engines for peer-reviewed articles, scientific reports, and MA and PhD theses concerning TFL changes. Results Most articles indicate TFL rise, but with high variability. Single factors that have an impact on TFL dynamics are well understood, but knowledge gaps exist with regard to interactions and feedbacks, especially those leading to distributional time lags. Extracting the most relevant factors for TFL changes, especially with regard to climate versus land-use changes, requires more research. Conclusions Existing data on TFL dynamics provide a broad overview of past and current changes, but estimations of reliable TFL changes for Norway as a whole is impossible. The main challenges in future empirically-based predictions of TFLs are to understand causes of time lags, separate effects of contemporary processes, and make progress on the impacts of feedback and interactions. Remapping needs to be continued, but combined with both the establishment of representative TFL monitoring sites and field experiments.
Vitenskapelig – Trait-dependent distributional shifts in fruiting of common British fungi
Alan C. Gange, Einar Heegaard, Lynne Boddy, ...
Despite the dramatic phenological responses of fungal fruiting to recent climate warming, it is unknown whether spatial distributions of fungi have changed and to what extent such changes are influenced by fungal traits, such as ectomycorrhizal (ECM) or saprotrophic lifestyles, spore characteristics, or fruit body size. Our overall aim was to understand how climate and fungal traits determine whether and how species‐specific fungal fruit body abundances have shifted across latitudes over time, using the UK national database of fruiting records. The data employed were recorded over 45 yr (1970–2014), and include 853 278 records of Agaricales, Boletales and Russulales, though we focus only on the most common species (with more than 3000 records each). The georeferenced observations were analysed by a Bayesian inference as a Gaussian additive model with a specification following a joint species distribution model. We used an offset, random contributions and fixed effects to isolate different potential biases from the trait‐specific interactions with latitude/climate and time. Our main aim was assessed by examination of the three‐way‐interaction of trait, predictor (latitude or climate) and time. The results show a strong trait‐specific shift in latitudinal abundance through time, as ECM species have become more abundant relative to saprotrophic species in the north. Along precipitation gradients, phenology was important, in that species with shorter fruiting seasons have declined markedly in abundance in oceanic regions, whereas species with longer seasons have become relatively more common overall. These changes in fruit body distributions are correlated with temperature and rainfall, which act directly on both saprotrophic and ECM fungi, and also indirectly on ECM fungi, through altered photosynthate allocation from their hosts. If these distributional changes reflect fungal activity, there will be important consequences for the responses of forest ecosystems to changing climate, through effects on primary production and nutrient cycling.
Vitenskapelig – The burden of sustainability: Limits to sustainable bioenergy development in Norway
This paper analyses the case of bioenergy development in Norway – drawing on Hedmark county located on the borders with Sweden – from a social, economic and environmental perspective (triple bottom line). Since 2008, the number of forest-based bioenergy plants increased rapidly, following the introduction of the wood-chips scheme and the high local expectations of its benefits for rural development. Obstacles to its continuous sustainable development have subsequently been increasing. Therefore, the goal of the study is to investigate the causal processes of bioenergy development to understand what threatens its triple bottom line sustainability. The study does so by employing qualitative system dynamics (i.e. causal loop diagram) and using interviews with local actors to elaborate on studies that look at the influence of power, institutions and expectations on the transition processes. Results show that the local actors’ positive perceptions of the benefits of bioenergy mainly drove its initial development, but that conflicting local interests, power relations, and market dynamics now threaten these initially positive perceptions.
Vitenskapelig – Microbial biogas production from hydrolysis lignin: Insight into lignin structural changes
Daniel Girma Mulat, Janka Dibdiakova, Svein Jarle Horn
Background: The emerging cellulosic bioethanol industry will generate huge amounts of lignin-rich residues that may be converted into biogas by anaerobic digestion (AD) to increase the output of energy carriers from the biorefnery plants. The carbohydrates fraction of lignocellulosic biomass is degradable, whereas the lignin fraction is generally considered difcult to degrade during AD. The objective of this study was to investigate the feasibility of biogas production by AD from hydrolysis lignin (HL), prepared by steam explosion (SE) and enzymatic saccharifcation of birch. A novel nylon bag technique together with two-dimensional nuclear magnetic resonance spectroscopy, pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), and Fourier transform infrared (FTIR) spectroscopy was used to identify recalcitrant and degradable structures in the lignin during AD. Results: The HL had a lignin content of 80% which included pseudo-lignin and condensed-lignin structures resulting from the SE pretreatment. The obtained methane yield from HL was almost twofold higher than the theoretical methane from the carbohydrate fraction alone, indicating that part of the lignin was converted to methane. Characterization of the undegradable material after AD revealed a substantial loss of signals characteristic for carbohydrates and lignin–carbohydrate complexes (LCC), indicating conversion of these chemical components to methane during AD. The β-O-4′ linkage and resinol were not modifed as such in AD, but major change was seen for the S/G ratio from 5.8 to 2.6, phenylcoumaran from 4.9 to 1.0%, and pseudo-lignin and condensed-lignin were clearly degraded. Scanning electron microscopy and simultaneous thermal analysis measurements demonstrated changes in morphology and thermal properties following SE pretreatment and AD. Our results showed that carbohydrate, LCC, pseudo-lignin, and condensed-lignin degradation had contributed to methane production. The energy yield for the combined ethanol production and biogas production was 8.1 MJ fuel per kg DM of substrate (4.9 MJ/kg from ethanol and 3.2 MJ/kg from methane). Conclusion: This study shows the beneft of using a novel bag technique together with advanced analytical techniques to investigate the degradation mechanisms of lignin during AD, and also points to a possible application of HL produced in cellulosic bioethanol plants.
Vitenskapelig – Runoff prediction in ungauged catchments in Norway: comparison of regionalization approaches
Xue Yang, Jan Magnusson, Jonathan Rizzi, ...
Runoff prediction in ungauged catchments has been a challenging topic over recent decades. Much research have been conducted including the intensive studies of the PUB (Prediction in Ungauged Basins) Decade of the International Association for Hydrological Science. Great progress has been made in the field of regionalization study of hydrological models; however, there is no clear conclusion yet about the applicability of various methods in different regions and for different models. This study made a comprehensive assessment of the strengths and limitations of existing regionalization methods in predicting ungauged stream flows in the high latitudes, large climate and geographically diverse, seasonally snow-covered mountainous catchments of Norway. The regionalization methods were evaluated using the water balance model – WASMOD (Water And Snow balance MODeling system) on 118 independent catchments in Norway, and the results show that: (1) distance-based similarity approaches (spatial proximity, physical similarity) performed better than regression-based approaches; (2) one of the combination approaches (combining spatial proximity and physical similarity methods) could slightly improve the simulation; and (3) classifying the catchments into homogeneous groups did not improve the simulations in ungauged catchments in our study region. This study contributes to the theoretical understanding and development of regionalization methods.
Vitenskapelig – Congruency in fungal phenology patterns across dataset sources and scales
Carrie Joy Andrew, Einar Heegaard, Alan C. Gange, ...
Vitenskapelig – Field screening of waterlogging tolerance in spring wheat and spring barley
Tove Sundgren, Anne Kjersti Uhlen, Wendy Marie Waalen, ...
Improved waterlogging tolerance of wheat and barley varieties may alleviate yield constraints caused by heavy or long-lasting precipitation. The waterlogging tolerance of 181 wheat and 210 barley genotypes was investigated in field trials between 2013 and 2014. A subset of wheat genotypes were selected for yield trials in 2015 and 2016. Our aim was to: (1) characterize the waterlogging tolerance of genotypes with importance for Norwegian wheat and barley breeding, and (2) identify which phenotypic traits that most accurately determine the waterlogging tolerance of wheat in our field trials. Waterlogging tolerance was determined by principal component analysis (PCA) where best linear unbiased predictors (BLUPs) of the traits chlorosis, relative plant height, heading delay, relative spike number, relative biomass and an overall condition score were used as input variables. Six wheat and five barley genotypes were identified as consistently more tolerant in 2013 and 2014. This included the waterlogging tolerant CIMMYT line CETA/Ae. tauschii (895). Chlorosis and the overall condition score were the traits that best explained the yield response of the genotypes selected for the yield trials. Our results show that early stress symptoms did not necessarily reflect the ability to recover post treatment. Thus, records from full crop cycles appear as fundamental when screening populations with unknown tolerance properties.
Vitenskapelig – Explaining European fungal fruiting phenology with climate variability
Carrie Joy Andrew, Einar Heegaard, Klaus Høiland, ...
Here we assess the impact of geographically dependent (latitude, longitude, and alti-tude) changes in bioclimatic (temperature, precipitation, and primary productivity) variability on fun-gal fruiting phenology across Europe. Two main nutritional guilds of fungi, saprotrophic andectomycorrhizal, were further separated into spring and autumn fruiters. We used a path analysis toinvestigate how biogeographic patterns in fungal fruiting phenology coincided with seasonal changesin climate and primary production. Across central to northern Europe, mean fruiting varied byapproximately 25 d, primarily with latitude. Altitude affected fruiting by up to 30 d, with springdelays and autumnal accelerations. Fruiting was as much explained by the effects of bioclimatic vari-ability as by their large-scale spatial patterns. Temperature drove fruiting of autumnal ectomycorrhizaland saprotrophic groups as well as spring saprotrophic groups, while primary production and precipi-tation were major drivers for spring-fruiting ectomycorrhizal fungi. Species-specific phenology predic-tors were not stable, instead deviating from the overall mean. There is significant likelihood thatfurther climatic change, especially in temperature, will impact fungal phenology patterns at largespatial scales. The ecological implications are diverse, potentially affecting food webs (asynchrony),nutrient cycling and the timing of nutrient availability in ecosystems.
Vitenskapelig – Estimation of phosphorus-based flame retardant in wood by hyperspectral imaging—a new method
Petter Stefansson, Ingunn Burud, Thomas Kringlebotn Thiis, ...
It is recognised that flame retardant chemicals degrade and leach out of flame-protected wood claddings when exposed to natural weathering. However, the ability to survey the current state of a flame retardant treatment applied to a wood cladding, an arbitrary length of time after the initial application, is limited today. In this study, hyperspectral imaging in the near infrared to short-wavelength infrared region is used to quantify the amount of flame retardant present on wooden surfaces. Several sets of samples were treated with various concentrations of a flame retardant chemical and scanned with a push broom hyperspectral camera. An inductively coupled plasma (ICP) spectroscopy analysis of the outermost layer of the treated samples was then carried out in order to determine each sample’s phosphorus content, the active ingredient in the flame retardant. Spectra from the hyperspectral images were pre-processed with extended multiplicative scatter correction, and the phosphorus content was modelled using a partial least squares (PLS) regression model. The PLS regression yielded robust predictions of surface phosphorus content with a coefficient of determination, R2, between 0.8 and 0.9 on validation data regardless of whether the flame retardant chemical had been applied to the surface of the wood or pressure-impregnated into it. The result from the study indicates that spectral imaging around the 2400–2531nm wavelength region is favourable for quantifying the amount of phosphorus-based flame retardant contained in the outermost layer of non-coated wooden claddings. The results also reveal that the uptake of phosphorus-based flame retardant does not occur uniformly throughout the wood surface, but is to a larger extent concentrated in the earlywood regions than in the latewood.
Vitenskapelig – Environmental load of pesticides used in conventional sugarcane production in Malawi
Trust Kasambala Donga, Ole Martin Eklo
The sugarcane industry is the third largest user of pesticides in Malawi. Our aim with this study was to document pesticide use and handling practices that influence pesticide exposure among sugarcane farmers in Malawi. A semi-structured questionnaire was administered to 55 purposively selected sugarcane farmers and 7 key informants representing 1474 farmers in Nkhata Bay, Nkhotakota and Chikwawa Districts in Malawi. Our results indicate that herbicides and insecticides were widely used. Fifteen moderately and one extremely hazardous pesticide, based on World Health Organization (WHO) classification, were in use. Several of these pesticides: ametryn, acetochlor, monosodium methylarsonate and profenofos are not approved in the European Union because of their toxicity to terrestrial and aquatic life, and/or persistence in water and soil. Farmers (95%) knew that pesticides could enter the human body through the skin, nose (53%) and mouth (42%). They knew that pesticide runoff (80%) and leaching (100%) lead to contamination of water wells. However, this knowledge was not enough to motivate them to take precautionary measures to reduce pesticide exposure. Farmers (78%) had experienced skin irritation, 67% had headache, coughing and running nose during pesticide handling. Measures are in place to reduce pesticide exposure in the large estates and farms operated by farmer associations. Smallholder farmers acting independently do not have the resources and capacity to minimize their exposure to pesticides. There is need to put in place pesticide residue monitoring programs and farmer education on commercial sugarcane production and safe pesticide use as ways of reducing pesticide exposure.
Vitenskapelig – The complexity of interacting nutritional drivers behind food selection, a review of northern cervids
Annika M. Felton, Hilde Karine Wam, Caroline Stolter, ...
The research literature on food selection by large herbivores is extensive. Still, we are generally lacking in our knowledge of the inﬂuence of potentially interacting chemical contents of the food. We made a qualitative review of a systematic literature search of studies that empirically link chemical contents of food to the food selection by northern cervids (genera Alces, Capreolus, Cervus, Dama, Odocoileus, Rangifer). We found that although the majority of the 98 relevant studies measuring any given food constituent (energy, protein, ﬁber, minerals, plant secondary metabolites) provided support for it acting as a driver of food selection (in either a negative or positive way), there was little support for the traditional hypotheses of maximization or limitation of any single constituent. Rather, because of the animals’ need to acquire an appropriate intake of several constituents at the same time, our review highlights how new empirical stud- ies need to focus on several food constituents in synchrony: (1) Study designs should capture sufﬁcient variation in the content of food constituents in order to tease apart their many co-variations; and (2) insights about nutritional drivers may be lost if one uses only composite currencies such as crude energy, crude ﬁber, ash, or tannins, which may mask contrasting selection patterns of the lumped constituents. Season had an apparent inﬂuence on the selection of some food constituents, particularly various ﬁber frac- tions. In contrast, our review revealed a lack of evidence that cervids more strongly select for protein in summer than they do in winter. Our overall conclusion of the review is that interacting chemical contents of food make the nutritional value of a given food type into a varying entity. To better elucidate this varia- tion, we need new technologies that non-invasively capture nutrient intake of free-ranging animals, across seasons.
Vitenskapelig – Cyclic small rodents in boreal forests and the effects of even-aged forest management: Patterns and predictions from a long-term study in southeastern Norway
Per Wegge, Jørund Rolstad
Small mammals, especially microtine rodents, play an important role in the dynamics of boreal forest ecosystems. Even-aged forest management, in which old, semi-natural forests are converted to clear-cuts and culturally regenerated stands, is expected to have pronounced impact on the abundance and composition of this group of animals due to changes in the understory vegetation. During a 39 year-period we sampled autumn numbers of small mammals in uncut, semi-natural old forest and in recent clearcuts, supplemented by a 7-year sample from middle-aged plantations. Field voles Microtus agrestis were almost exclusively trapped in clearcuts. Bank voles Myodes glareolus dominated in the old forest, but reached equal or higher densities than field voles in clearcuts. Here, their combined abundance exceeded that of bank voles in old forest. Some years, wood lemmings Myopus schisticolor contributed significantly to vole abundance in old forest. Other rodents Apodemus spp. were rarely captured, mainly in clearcuts, and shrews Sorex spp. numbered < 15 percent of the total number of captured animals. Throughout the whole period we discerned 11 vole cycles, with highest peaks in bank voles in old forest. After high numbers during the 1980s, abundances of all species fell markedly during the 1990s, most distinctively in clearcuts, where the field vole almost totally disappeared. From the late 2000s, abundances of all species returned to pre-1990 levels and beyond. In the early and late periods, combined vole numbers were 26% higher in clearcuts compared to old forest, whereas the opposite was true in the middle period. In middle-aged plantations, bank voles numbered only one third of what it was in clearcuts and old forest, and other voles were rarely trapped. The results support the general notion that bank voles thrive in bilberry-rich, older forest and field voles in grass-dominated habitat. Contrary to general assertions, bank vole was abundant also in clearcuts, possibly due to invasion from surrounding old forest, but peak densities were lower than in old forest, possibly due to suppression by field voles. The variation of small mammals in forest age classes concurred closely with recent results reported from Finland. On a landscape scale, the results from these two and other studies predict that the total biomass of small rodents will be reduced by even-aged forest management, not because of conversion of older, semi-natural forest to clearcuts, but because of a decline in numbers in middle-aged and older, secondary forests.
Vitenskapelig – Control of growth cessation and floral initiation in red raspberry (Rubus idaeus L.) cultivars of diverse origin in controlled and natural environments
Randi Hodnefjell, Ola M Heide, Rodmar Isak Rivero, ...
The aim of the investigation was to assess and compare the environmental limits for growth cessation and ﬂoralinitiation in a range of new and established biennial-fruiting red raspberry (Rubus idaeus L.) cultivars of diverseorigin under phytotron and ﬁeld conditions. The results conﬁrmed that growth cessation and ﬂoral initiation inbiennial-fruiting red raspberry are jointly controlled by the interaction of low temperature and short days (SD).When transferred from non-inductive high temperature and long day (LD) conditions to naturally decreasingautumn daylengths at varying phytotron temperatures on 18 August, growth immediately levelled oﬀ and ceasedcompletely within 2 weeks in all cultivars at 9 °C. Serial dissections of lateral buds revealed that ﬂoral initiationsimultaneously took place. At 15 °C on the other hand, the plants continued growing and remained vegetativeuntil around 15 September when the daylength had decreased to approximately 13 h. The change to 9 °C resultedin an immediate but short-lasting ﬂoral induction response that did not bring about initiation in buds situatednear the base of the canes, as was the case at 15 °C. At 18 °C, marginal ﬂoral induction took place only in thecultivars ‘Glen Ample’, ‘Balder’ and ‘Vene’, even at photoperiods down to 10 h, whereas at 21 °C, all cultivarsgrew vegetatively regardless of daylength conditions. However, exceptions were some plants of ‘Vene’ and‘Anitra’ that initiated terminal ﬂowers at 18 and 21 °C and ﬂowered directly without chilling (so-called tipﬂowering). Although some cultivars of Northern origin ceased growing and initiated ﬂoral primordia somewhatearlier (at longer photoperiods) than those of more southerly origin, the diﬀerences were relatively minor andnot consistent (no latitudinal cline). Results obtained in the ﬁeld under decreasing autumn temperature anddaylength conditions agreed closely with the results in the phytotron. We therefore conclude that results ob-tained with raspberry in properly controlled daylight phytotron experiments are generally applicable to ﬁeldconditions.
Vitenskapelig – Recycling of biogas digestates in plant production: NPK fertilizer value and risk of leaching
Trine Aulstad Sogn, Ivan Dragicevic, Roar Linjordet, ...
Purpose The main purposes of the study were to assess the NPK fertilizer value of biogas digestates in different soils and to evaluate the risk of unwanted nutrient leaching. Methods The fertilizer value of digestates from anaerobic digesters was investigated in a greenhouse pot experiment with wheat in three different soils; silt, loam and sand. The digestates were based on different feedstock and had a low, dry matter