Marit Jørgensen
Senior Research Scientist
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Akhil Reddy Pashapu Sigridur Dalmannsdottir Marit Jørgensen Marian Schubert Odd Arne Rognli Mallikarjuna Rao KoviAbstract
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Appropriate weed control measures during the renewal phase of temporary grasslands are critical to ensure high yields during the whole grassland lifecycle. The aim of this study was to determine which integrated grassland renewal strategy can most effectively control annual weeds in the sowing year and delay perennial weed re-establishment. Four split-plot trials were established at three sites dominated by Rumex spp. along a south-north gradient in Norway. The annual and perennial weed abundance was recorded during the sowing year and two or three production years. Main plots tested seven renewal strategies: 1. Spring plowing, 2. Spring plowing+companion crop (CC), 3. Summer cut+plowing, 4. Summer glyphosate+plowing, 5. Summer glyphosate+harrowing, 6. Late spring glyphosate+plowing, 7. Fall glyphosate+spring plowing+CC. Strategies 1–4 were tested in all four trials, strategy 5 in three trials, strategy 6 in two trials and strategy 7 in one trial. Plowing was performed at 20–25 cm depth, rotary harrowing at 15 cm depth, and glyphosate was applied at 2160 g a.i. ha-1. CC was spring barley (Hordeum vulgare). Subplots tested selective herbicide spraying (yes/no) in the sowing year. Results showed that effects of renewal strategies were often site-specific and differed between the sowing year and production years. Spring renewal resulted in higher perennial weed abundance than summer renewal in two out of four trials (by 3 and 12 percentage points, over all production years), and glyphosate followed by harrowing drastically increased Rumex spp. in one out of three trials (by 18 percentage points over all production years). CCs only significantly reduced perennial weed abundance in one trial (by 8 percentage points over all production years). In comparison, the selective herbicides had a strong effect on annual and perennial weeds in the sowing year in all trials. Selective herbicides reduced the weed cover from 32% to 7% cover, and averaged over the production years and sites, the perennial weed biomass fraction was 6 percentage points lower where herbicides had been applied. We conclude that while the tested renewal strategies provided variable and site-specific perennial weed control, selective herbicides were effective at controlling Rumex spp. and other perennial dicot weeds in the first two production years.
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Ethiopia has the highest livestock numbers in Africa, and a large part of the population depends fully or partly on cattle for their livelihoods. The country experiences high rates of soil erosion due to degradation of cropland and rangelands, and overgrazing is a serious problem. In this paper, we report results from the first two harvests of two field experiments established in June 2021 at two different highland locations in Ethiopia: Hawassa in the south, and Bahir Dar in the north. Four species; two legumes (Desmodium intortum and Stylosanthes guianensis) and two grasses (Brachiaria hybrid ‘Cayman’ and Panicum maximum ‘Mombasa’) were sown in monocultures and various mixtures in a simplex design. Dry matter yields and botanical composition from each cut were recorded. The first harvest was taken around 100 days after establishment, while the second harvest was taken during the drought period, i.e. in January 2022 at Hawassa and in March 2022 at Bahir Dar. The difference between monoculture and mixture community performances varied in magnitude from site to site and across harvests; we found evidence of positive interactions between grasses and legumes at Hawassa. These preliminary results show that grass-legume mixtures using tropical species have some potential under Ethiopian conditions.
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Marit JørgensenAbstract
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Odd Arne Rognli Trygve S. Aamlid Muath K Alsheikh Helga Amdahl Sigridur Dalmannsdottir Kristoffer Herland Hellton Marit Jørgensen Mallikarjuna Rao Kovi Therese Mæland Akhil Reddy Pashapu Ievina Sturite Thordis Linda Thorarinsdottir Susanne Skinnehaugen WindjuAbstract
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Productive and stable forage yields are essential for the sustainability of ruminal livestock production. Grassland seed mixtures composed of species of diverse functional groups have previously been demonstrated to increase yield performance and stability compared to monocultures. In this study we conducted field trials with five grass and two legume species either grown in monocultures or a range of mixtures from two-species to seven-species mixtures sown in a simplex design. The species represented different functional groups regarding ability to fixate atmospheric nitrogen (N), rate of establishment and temporal persistence.The experiments were established with the same cultivars of species at five locations in Norway with climatically contrasting environments – from mild humid, mountainous continental to sub-arctic. The experimental plots were harvested for three years at four of the sites and two years at one of the sites, and they were fertilised according to normal practise in intensive silage grass production in the respective regions (regular N). At three of the sites, a treatment with low mineral N supply rate was also included.We found that crops sown as mixtures returned higher yields and contained less weeds than the average of monoculture crops, and these effects were consistent over all sites and study years. The grass-legume mixtures managed at low N supply rate performed equally well or better than monocultures or grass-only mixtures managed at regular N supply. We found no effects of the functional groups categorised as temporal persistence or rate of establishment on the yield performance, and there were no apparent benefits of increasing the number of species beyond the species P. pratense, F. pratensis and T. pratense over the three production years the experiments lasted.The results suggest that by using grass-clover mixtures, farmers can reduce N fertiliser rates, without compromising productivity of temporary grassland under northern conditions over the first three years of production.
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Kristoffer Herland Hellton Helga Amdahl Thordis Thorarinsdottir Muath K Alsheikh Trygve S. Aamlid Marit Jørgensen Sigridur Dalmannsdottir Odd Arne RognliAbstract
The perennial forage grass timothy (Phleum pratense L.) is the most important forage crop in Norway. Future changes in the climate will affect growing conditions and hence the yield output. We used data from the Norwegian Value for Cultivation and Use testing to find a statistical prediction model for total dry matter yield (DMY) based on agro-climatic variables. The statistical model selection found that the predictors with the highest predictive power were growing degree days (GDD) in July and the number of days with rain (>1mm) in June–July. These predictors together explained 43% of the variability in total DMY. Further, the prediction model was combined with a range of climate ensembles (RCP4.5) to project DMY of timothy for the decades 2050–2059 and 2090–2099 at 8 locations in Norway. Our projections forecast that DMY of today’s timothy varieties may decrease substantially in South-Eastern Norway, but increase in Northern Norway, by the middle of the century, due to increased temperatures and changing precipitation patterns.
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Climate change results in longer growing season, benefitting forage crop production in northern Norway. Wild goose populations take advantage of the increased access to this high-quality feed. European goose populations are increasing, triggering conflicts and economical losses for farmers. A warmer climate may open for higher yielding seed mixtures, with better tolerance against goose grazing. We tested eight different seed mixtures by adding five forage species in various combinations to a traditional, commercial seed mixture in a randomized block design, three replicates. Goose grazing was simulated by weekly cutting small plots (0.25 m2) fixed within 10.5 m2 larger plots. Cumulated biomass in the weekly cut small plots was compared to total yields from the large plots, harvested twice according to normal practice. No significant differences in biomass accumulation between seed mixtures of the weekly cut plots were identified, possibly due to large variation between replicates, harvest years and cutting regime. However, results indicate that several of the new mixtures containing Dactylis glomerata are higher yielding and tolerate intensified cutting better than the traditional mixtures. This suggests that traditional, commercial seed mixtures are not the best for grasslands subjected to intensive geese grazing. goose grazing, Northern Norway, Dactylis glomerata, field study, simulated grazing
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The impact of weather, soil and management on yield and nutritive value of grassland can be evaluated using process-based simulation models. These models may be calibrated using data on biomass, leaf area and other characteristics acquired from drones, hand-held devices, and satellites. The objective of this study was to compare the prediction accuracy of the BASGRA model calibrated with grassland data from Northern Norway obtained in 2016 and 2017. The data were acquired either from: (1) ground registrations; or (2) a hand-held spectrometer and satellites. Data on crude protein and fibre content from NIRS analyses were used in both calibrations. Daily air temperature, precipitation, relative air humidity, wind speed and solar radiation that were input to the BASGRA simulations were taken from The Norwegian Meteorological Institute and The Agrometeorology Norway network. Information about soil texture, cutting regime and N fertilization was obtained from farmers and advisers. The differences between simulated and observed biomass, and crude protein and fibre content were similar after the two calibrations. Observed crude protein and fibre content were simulated with a higher accuracy than biomass for both types of calibration data.
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Marit JørgensenAbstract
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Marit JørgensenAbstract
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This study investigated the potential of in-season airborne hyperspectral imaging for the calibration of robust forage yield and quality estimation models. An unmanned aerial vehicle (UAV) and a hyperspectral imager were used to capture canopy reflections of a grass-legume mixture in the range of 450 nm to 800 nm. Measurements were performed over two years at two locations in Southeast and Central Norway. All images were subject to radiometric and geometric corrections before being processed to ortho-images, carrying canopy reflectance information. The data (n = 707) was split in two, using half the data for model calibration and the remaining half for validation. Several powered partial least squares regression (PPLSR) models were fitted to the reflectance data to estimate fresh (FM) and dry matter (DM) yields, as well as crude protein (CP), dry matter digestibility (DMD), neutral detergent fibre (NDF), and indigestible neutral detergent fibre (iNDF) content. Prediction performance of these models was compared with the prediction performance of simple linear regression (SLR) models, which were based on selected vegetation indices and plant height. The highest prediction accuracies for general models, based on the pooled data, were achieved by means of PPLSR, with relative root-mean-square errors of validation of 14.2% (2550 kg FM ha−1), 15.2% (555 kg DM ha−1), 11.7% (1.32 g CP 100 g−1 DM), 2.4% (1.71 g DMD 100 g−1 DM), 4.8% (2.72 g NDF 100 g−1 DM), and 12.8% (1.32 g iNDF 100 g−1 DM) for the prediction of FM, DM, CP, DMD, NDF, and iNDF content, respectively. None of the tested SLR models achieved acceptable prediction accuracies.
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Marit JørgensenAbstract
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Farmers in Northern Norway frequently experience winter damaged fields caused by ice encasement. The economic consequences are severe due to loss of fodder and costs with reestablishment of swards. It is therefore important to choose the best available varieties for the local climatic and environmental conditions. We tested eight Norwegian cultivars of timothy (Phleum pratense), for tolerance to ice encasement and their regrowth capacity. Both old and new cultivars, and cultivars with good overwintering capacity and less biomass production were tested against more productive cultivars with less overwintering capacity. The experiment was a semi-field setup and plants were established in pots which were placed outside. Half of the pots were covered with ice and half were kept under snow cover. During four months, pots were brought, once per month, into a greenhouse for thawing and measurement of biomass production under normal growth conditions. The results indicate that the old winter hardy cultivar ‘Engmo’ is least affected by ice encasement but produces little biomass. The joint Nordic cultivar ‘Snorri’ produced most biomass of all the cultivars after a treatment with ice cover. In conclusion, there is a large difference between cultivars in ice encasement tolerance, and ice cover affected regrowth capacity far more than snow cover
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Perennial ryegrass (Lolium perenne L.) is not widely used in forage production in Norway; until recently only in regions with very mild winter climate. Due to its high digestibility and yield potential, and trends towards milder winters, the interest for using this species in silage production has increased. However, variable winter weather with frost and ice can damage perennial ryegrass extensively, and it is therefore regarded as a rather short-lived species under these conditions. In this paper, we report results from field experiments for first-year leys established in 2016 at three different locations from south to north in Norway. Different seed mixtures of grass and clover species were sown with and without the addition of perennial ryegrass. In 2017, plots were fertilised with either medium level of nitrogen (N) or low N-level (half of the medium level). Dry matter yields, botanical composition and feed quality (determined by NIRS) from each cut were recorded. Perennial ryegrass dominated in all mixtures and reduced weed invasion, regardless of location. Inclusion of ryegrass led to higher yield production compared to mixtures without ryegrass; it increased digestibility but the content of crude protein tended to be lower, probably due to a dilution effect caused by the higher yield production.
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Precipitation has generally increased in Norway during the last century, and climate projections indicate a further increase. The growing season has also become longer with higher temperatures, particularly in autumn. Previous studies have shown negative effects of high temperatures and, depending upon temperature conditions, contrasting effects of waterlogging on hardening capacity of timothy. We studied effects of waterlogging on seedlings of timothy (Phleum pratense, cv. Noreng) under three pre‐acclimation temperatures: 3°C, 7°C, 12°C, and in autumn natural light in a phytotron at Holt, Tromsø (69°N). After temperature treatments, all plants were cold acclimated at 2°C for three weeks under continued waterlogging treatments. Freezing tolerance was determined by intact plants being frozen in pots at incremental temperature decreases in a programmable freezer. Waterlogging resulted in a higher probability of death after freezing, and a significantly reduced regrowth after three weeks at 18°C, 24 hrs light in a greenhouse. Increasing pre‐acclimation temperatures also had a clear negative effect on freezing tolerance, but there was no interaction between temperatures and waterlogging. The results indicate that waterlogging may have negative implications for hardening of timothy and may contribute to reduced winter survival under the projected increase in autumn temperatures and precipitation.
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Marit Jørgensen Corine Davids Francisco Javier Ancin Murguzur Jørgen A.B. Mølmann Gregory TaffAbstract
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Francisco Javier Ancin Murguzur Gregory Taff Corine Davids Hans Tømmervik Jørgen A.B. Mølmann Marit JørgensenAbstract
Ruminant fodder production in agricultural lands in latitudes above the Arctic Circle is constrained by short and hectic growing seasons with a 24-hour photoperiod and low growth temperatures. The use of remote sensing to measure crop production at high latitudes is hindered by intrinsic challenges, such as a low sun elevation angle and a coastal climate with high humidity, which influences the spectral signatures of the sampled vegetation. We used a portable spectrometer (ASD FieldSpec 3) to assess spectra of grass crops and found that when applying multivariate models to the hyperspectral datasets, results show significant predictability of yields (R2 > 0.55, root mean squared error (RMSE) < 180), even when captured under sub-optimal conditions. These results are consistent both in the full spectral range of the spectrometer (350–2500 nm) and in the 350–900 nm spectral range, which is a region more robust against air moisture. Sentinel-2A simulations resulted in moderately robust models that could be used in qualitative assessments of field productivity. In addition, simulation of the upcoming hyperspectral EnMap satellite bands showed its potential applicability to measure yields in northern latitudes both in the full spectral range of the satellite (420–2450 nm) with similar performance as the Sentinel-2A satellite and in the 420–900 nm range with a comparable reliability to the portable spectrometer. The combination of EnMap and Sentinel-2A to detect fields with low productivity and portable spectrometers to identify the fields or specific regions of fields with the lowest production can help optimize the management of fodder production in high latitudes.
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Knowledge about the botanical composition of grassland for silage is important regarding composition of seed mixtures, control of weeds, choice of harvest times and feeding strategies. The botanical composition of 185 fields in the mountain regions of southern Norway was examined using the dryweight rank method. The survey shows that the youngest grasslands (age 1 - 3 years) were dominated by the sown species with Phleum pratense L. the species with the highest proportion in the sward. In 4 - 6 year old grasslands, the proportion of sown species was reduced with the exception of Poa pratensis L., and Elytrigia repens L. had the highest proportion of unsown species. The proportion of Festuca pratensis (Huds.) was reduced at the same rate as Phleum pratense L. In grasslands of greater age (> 6 years) Poa pratensis L. and Elytrigia repens L. had the highest occurrence. The content of herbs increased with age, and Ranunculus repens L. and Taraxacum officinale F.H. Wigg were the most frequent species. The average clover content was < 6% of DM yield. The impact of Elytrigia repens L. on forage yield and quality should be further examined due to the high occurrence. Poa pratensis L. or other long-lasting grass species should be included in seed mixtures for this region when the grassland is intended to last more than three years.
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Caroline Brophy John A. Finn Andreas Lüscher M. Suter Laura Kirwan Maria-Teresa Sebastià Aslaug Helgadottir Ole Hans Baadshaug G. Bélanger Alistair Black Rosemary P. Collins Jure Čop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Mick Fothergill Bodil E. Frankow-Lindberg An Ghesquiere Barbara Golinska Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Päivi Kurki Rosa Llurba Tor Lunnan Claudio Porqueddu Ulrich Thumm John ConnollyAbstract
Increasing species diversity often promotes ecosystem functions in grasslands, but sward diversity may be reduced over time through competitive interactions among species. We investigated the development of species’ relative abundances in intensively managed agricultural grassland mixtures over three years to identify the drivers of diversity change. A continental-scale field experiment was conducted at 31 sites using 11 different four-species mixtures each sown at two seed abundances. The four species consisted of two grasses and two legumes, of which one was fast establishing and the other temporally persistent. We modelled the dynamics of the four-species mixtures over the three-year period. The relative abundances shifted substantially over time; in particular, the relative abundance of legumes declined over time but stayed above 15% in year three at many sites. We found that species’ dynamics were primarily driven by differences in the relative growth rates of competing species and secondarily by density dependence and climate. Alongside this, positive diversity effects in yield were found in all years at many sites.
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John Connolly Maria-Teresa Sebastià Laura Kirwan John A. Finn Rosa Llurba M. Suter Rosemary P. Collins Claudio Porqueddu Aslaug Helgadottir Ole Hans Baadshaug Gilles Bélanger Alistair Black Caroline Brophy Jure Čop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Mick Fothergill Bodil E. Frankow-Lindberg An Ghesquiere Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Tor Lunnan Päivi Nykanen-Kurki Angela Ribas Friedhelm Taube Ulrich Thumm A. De Vliegher Andreas LüscherAbstract
Weed suppression was investigated in a field experiment across 31 international sites. The study included 15 plant communities at each site, based on two grasses and two legumes, each sown in monoculture and 11 four-species mixtures varying in the relative proportions of the four species. At each site, one grass and one legume species was selected as fast establishing and the other two species were selected for persistence. Average weed biomass in mixtures over the whole experiment was 52% less (95% confidence interval, 30 to 75%) than in the most suppressive monoculture (transgressive suppression). Transgressive suppression of weed biomass persisted over each year for each mixture. Weed biomass was consistently low and relatively similar across all mixtures and years. Average sown species biomass was greater in all mixtures than in any monoculture. The suppressive effect of sown forage species on weeds in mixtures was achieved without any herbicide use. At each site, weed biomass for almost every mixture was lower than the average across the four monocultures. The average proportion of weed biomass in mixtures was less than in the most suppressive monoculture in two thirds of sites. Mixtures outyielded monocultures, and mixture yield comprised far lower weed biomass.
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Piotr Goliński Marek Czerwiński Marit Jørgensen Jørgen A.B. Mølmann Barbara Golińska Gregory TaffAbstract
We investigated climatic trends in two contrasting locations in Europe at a regional level and at two specific sites, and we analysed how these trends are associated with the dry matter yield (DMY) of agriculturally improved grasslands. Trends of different meteorological variables were evaluated for Wielkopolska province, central Poland (1985-2014) and Troms county, northern Norway (1989-2015), as well as for two research stations located in these regions. Significant trends of increased mean air temperatures annually, and in April, June, July, August and November were identified both at the regional and site levels in Wielkopolska. In addition, growing degree days were increasing in Wielkopolska. In Troms, the common trends for the region and site studied were increase in mean air temperature in May and decrease in January. Grassland DMY was subsequently regressed against those meteorological variables for which significant trends were detected. In the Wielkopolska region, yields were negatively associated with the increase in air temperature in June, August, and the annual air temperature. The last relationship was also detected at the site level. We did not find any significant effects of climate trends on grassland DMY in the Norwegian study site or region.
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In order to establish the relationship between spectral reflectance and grass yield, we used a UAV-based hyperspectral camera and ground-based spectroradiometry to image a number of cultivated grasslands of different age and productivity in northern Norway. In addition, samples were taken to determine biomass and grass species composition. We investigated a number of vegetation indices as well as regression analysis to identify which spectral reflectance features can be used to map crop yield. We found poor relationships between NDVI and yield, but were able to obtain an acceptable relationship using all 15 available bands in the visible-near infrared range. Bands in the near infrared appear to contain most of the information related to yield.
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Sigridur Dalmannsdottir Marit Jørgensen Marcin Rapacz Liv Østrem Arild Larsen Rolf Rødven Odd Arne RognliAbstract
The effect of variable autumn temperatures in combination with decreasing irradiance and daylength on photosynthesis, growth cessation and freezing tolerance was investigated in northern- and southern-adapted populations of perennial ryegrass (Lolium perenne) and timothy (Phleum pratense) intended for use in regions at northern high latitudes. Plants were subjected to three different acclimation temperatures; 12, 6 and 9/3°C (day/night) for 4 weeks, followed by 1 week of cold acclimation at 2°C under natural light conditions. This experimental setup was repeated at three different periods during autumn with decreasing sums of irradiance and daylengths. Photoacclimation, leaf elongation and freezing tolerance were studied. The results showed that plants cold acclimated during the period with lowest irradiance and shortest day had lowest freezing tolerance, lowest photosynthetic activity, longest leaves and least biomass production. Higher acclimation temperature (12°C) resulted in lower freezing tolerance, lower photosynthetic activity, faster leaf elongation rate and higher biomass compared with the other temperatures. Photochemical mechanisms were predominant in photoacclimation. The northern-adapted populations had a better freezing tolerance than the southern-adapted except when grown during the late autumn period and at the highest temperature; then there were no differences between the populations. Our results indicate that the projected climate change in the north may reduce freezing tolerance in grasses as acclimation will take place at higher temperatures and shorter daylengths with lower irradiance.
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Åshild Ergon Giovanna Seddaiu Panu Korhonen Perttu Virkajärvi Gianni Bellocchi Marit Jørgensen Liv Østrem Dirk Reheul F. VolaireAbstract
Climate change and its effects on grassland productivity vary across Europe. The Mediterranean and Nordic regions represent the opposite ends of a gradient of changes in temperature and precipitation patterns, with increasingly warmer and wetter winters in the north and increasingly warmer and drier summers in the south. Warming and elevated concentration of atmospheric CO2 may boost forage production in the Nordic region. Production in many Mediterranean areas is likely to become even more challenged by drought in the future, but elevated CO2 can to some extent alleviate drought limitation on photosynthesis and growth. In both regions, climate change will affect forage quality and lead to modifications of the annual productivity cycles, with an extended growing season in the Nordic region and a shift towards winter in the Mediterranean region. This will require adaptations in defoliation and fertilization strategies. The identity of species and mixtures with optimal performance is likely to shift somewhat in response to altered climate and management systems. It is argued that breeding of grassland species should aim to (i) improve plant strategies to cope with relevant abiotic stresses and (ii) optimize growth and phenology to new seasonal variation, and that plant diversity at all levels is a good adaptation strategy.
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Caroline Brophy John A. Finn Andreas Lüscher Matthias Suter Laura Kirwan Maria-Teresa Sebastià Áslaug Helgadóttir Ole Hans Baadshaug Gilles Bélanger Alistair Black Rosemary P. Collins Jure Čop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Michael Fothergill Bodil E. Frankow-Lindberg An Ghesquiere Barbara Golinska Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Päivi Kurki Rosa Llurba Tor Lunnan Claudio Porqueddu Ulrich Thumm John ConnollyAbstract
1. Increased species diversity promotes ecosystem function; however, the dynamics of multi-speciesgrassland systems over time and their role in sustaining higher yields generated by increased diver-sity are still poorly understood. We investigated the development of species’ relative abundances ingrassland mixtures over 3 years to identify drivers of diversity change and their links to yield diver-sity effects.2. A continental-scale field experiment was conducted at 31 sites using 11 different four-speci esmixtures each sown at two seed abundances. The four species consisted of two grasses and two legumes, of which one was fast establishing and the other temporally persistent. We modelledthe dynamics of the four-species mixtures, and tested associations with diversity effects on yield.3. We found that species’ dynamics were primarily driven by differences in the relative growth rates(RGRs) of competing species, and secondarily by density dependence and climate. The temporallypersistent grass species typically had the highest RGRs and hence became dominant over time. Den-sity dependence sometimes induced stabilising processes on the dominant species and inhibitedshifts to monoculture. Legumes persisted at most sites at low or medium abundances and persistencewas improved at sites with higher annual minimum temperature.4. Significant diver sity effects were present at the majority of sites in all years and the strength ofdiversity effects was improved with higher legume abundance in the previous year. Observed diver-sity effects, when legumes had declined, may be due to (i) important effects of legumes even at lowabundance, (ii) interaction between the two grass species or (iii) a store of N because of previouspresence of legumes.5. Synthesis. Alongside major compositional changes driven by RGR differences , diversity effectswere observed at most sites, albeit at reduced strength as legumes declined. This evidence stronglysupports the sowing of multi-species mixtures that include legumes over the long-standing practiceof sowing grass monocultures. Careful and strategic selection of the identity of the species used inmixtures is suggested to facilitate the maintenance of species diversity and especially persistence oflegumes over tim e, and to preser ve the strength of yield increases associated with diversity.
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John Connolly Maria-Teresa Sebastià Laura Kirwan John Anthony Finn Rosa Llurba Matthias Suter Rosemary P. Collins Claudio Porqueddu Áslaug Helgadóttir Ole Hans Baadshaug Gilles Bélanger Alistair Black Caroline Brophy Jure Čop Sigridur Dalmannsdottir Delgado Ignacio Anjo Elgersma Michael Fothergill Bodil E. Frankow-Lindberg Ghesquiere An Piotr Golinski Philippe Grieu Gustavsson Anne-Maj Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Tor Lunnan Paivi Nykanen-Kurki Angela Ribas Friedhelm Taube Ulrich Thumm Alex De Vliegher Andreas LüscherAbstract
1. Grassland diversity can support sustainable intensification of grassland production through increased yields, reduced inputs and limited weed invasion. We report the effects of diversity on weed suppression from 3 years of a 31-site continental-scale field experiment. 2. At each site, 15 grassland communities comprising four monocultures and 11 four-species mixtures based on a wide range of species' proportions were sown at two densities and managed by cutting. Forage species were selected according to two crossed functional traits, “method of nitrogen acquisition” and “pattern of temporal development”. 3. Across sites, years and sown densities, annual weed biomass in mixtures and monocultures was 0.5 and 2.0 t DM ha−1 (7% and 33% of total biomass respectively). Over 95% of mixtures had weed biomass lower than the average of monocultures, and in two-thirds of cases, lower than in the most suppressive monoculture (transgressive suppression). Suppression was significantly transgressive for 58% of site-years. Transgressive suppression by mixtures was maintained across years, independent of site productivity. 4. Based on models, average weed biomass in mixture over the whole experiment was 52% less (95% confidence interval: 30%–75%) than in the most suppressive monoculture. Transgressive suppression of weed biomass was significant at each year across all mixtures and for each mixture. 5. Weed biomass was consistently low across all mixtures and years and was in some cases significantly but not largely different from that in the equiproportional mixture. The average variability (standard deviation) of annual weed biomass within a site was much lower for mixtures (0.42) than for monocultures (1.77). 6. Synthesis and applications. Weed invasion can be diminished through a combination of forage species selected for complementarity and persistence traits in systems designed to reduce reliance on fertiliser nitrogen. In this study, effects of diversity on weed suppression were consistently strong across mixtures varying widely in species' proportions and over time. The level of weed biomass did not vary greatly across mixtures varying widely in proportions of sown species. These diversity benefits in intensively managed grasslands are relevant for the sustainable intensification of agriculture and, importantly, are achievable through practical farm-scale actions.
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Piotr Golinski Marit Jørgensen Marek Czerwiński Barbara Golińska Jørgen A.B. Mølmann Gregory TaffAbstract
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Piotr Golinski Marit Jørgensen Marek Czerwiński Barbara Golińska Jørgen A.B. Mølmann Gregory TaffAbstract
The aims of this study were: (1) to assess the trends of climatic variables in two contrasting geographical locations: central Poland and northern Norway; and (2) to evaluate the influence of the detected trends on timothy yields. This grass species was selected for its high importance for forage production in Norway as well as in Poland. For the assessment of climate trends, historical meteorological data, which cover time series from 1985 onwards, were used. Trends of various climate condition indicators were investigated. Data on timothy yields were collected beginning in the 1990s for Brody in Poland from cultivar testing experiments and Holt in Norway by the national cultivar-testing program. The results indicated that in central Poland air temperature in specific months significantly decrease the annual yield of timothy while in northern Norway many climatic variables, such as earlier start and prolonged length of growing season, may have a slightly positive impact on timothy productivity.
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Åshild Ergon F Volaire P Korhonen Perttu Virkajärvi G. Seddaiu Marit Jørgensen Gianni Bellocchi Liv Østrem D* Reheul Joost BaertAbstract
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Åshild Ergon F Volaire P Korhonen Perttu Virkajärvi G. Seddaiu Marit Jørgensen Gianni Bellocchi Liv Østrem D* Reheul Joost BaertAbstract
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Authors
Katarzyna Dabrowska-Zielinska Piotr Golinski Marit Jørgensen Jørgen A.B. Mølmann Gregory Taff Stanislaw Twardy Maria Budzynska Marek Czerwinski Marek Kopacz Robert Kurnicki Wanda Kowalik Monika Tomaszewska Alicja Malinska Barbara Golinska Martyna GatkowskaAbstract
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Abstract
The growing season is longer than earlier and especially autumn temperatures have increased during the last 30 years (Hanssen‐Bauer et al 2015). A longer growing season increases the potential for forage production as an earlier spring, and warmer autumn implies that farmers can take more cuts with larger yields than earlier. Nevertheless, a warmer autumn can promote considerable regrowth after the last cut, and farmers report that they are uncertain if this regrowth should be harvested. The cost of harvesting forage is high, and feed quality of late harvested forage may be sub‐optimal. Changing precipitation patterns where there may be more episodes of heavy rains during autumn, late harvesting of grass swards can increase the risk of soil compaction and damage plant cover. This was the background to a study where we examine how different harvest time in autumn affects overwintering and yields the following year. We have established randomized block field experiments with 3 replicates in established leys dominated by timothy (Phleum pratense L.) at two sites in Norway in 2015; Kvithamar 63o29’N, 10o53’E, and Holt 69o38’N, 18o57’E. In the Kvithamar field, the main harvests were made June 30 and August 10. Thereafter, in one treatment, plots were left unharvested till next spring, while in other treatments plots were cut 4, 6, 8 or 10 weeks after the second main harvest. At Holt, the first harvest was made July 7, and the second harvest either August 11 or August 27. The regrowth after these treatments were either left uncut or harvested 4, 6 or 8 weeks after the last main cut in August 10, or 6 weeks after the cut in August 28. Dry matter yields were measured from all cuts. The results were analysed using ANOVA with MiniTab. No significant differences in yields were found between the different cutting treatments at either site, even though temperatures were between 2.2‐ 2.5oC higher than normal (1961‐1990) in September and between 1.1‐1.6 warmer than normal in October. Global radiation decreases rapidly from September onwards, and is a limiting factor for the growth potential of timothy‐dominated leys. In spring, we will measure winter survival and growth rate and yields in all treatments. The results from these measurements will be presented at the conference.
Authors
Katarzyna Dabrowska-Zielinska Piotr Golinski Marit Jørgensen Jørgen A.B. Mølmann Gregory Taff Stanislaw Twardy Monika Tomaszewska Barbara Golińska Maria Budzynska Martyna Gatkowska M KopaczAbstract
Grasslands are significant as a source of forage for animal production, but are also important in many ecological functions. To be able to analyse changes in environmental conditions of grasslands, monitoring of grassland areas using remote sensing is an important task. Studying changes in environmental condition over time and space in grasslands has been the subject of research at different scales. Such an example is the Polish-Norwegian Research Project FINEGRASS „Effect of climatic changes on grassland growth, its water conditions and biomass’. In situ measured soil-vegetation parameters and satellite observations have been combined and analysed to quantify the spatial and temporal variability of grassland conditions, as reflected in variations of vegetation surface temperature, soil moisture, and biomass. Results show a significant trend of increasing grassland surface temperature in Poland, based on AVHRR satellite data; a positive significant relationship between the (April-September) standardized precipitation evapotranspiration index (SPEI) and grass yields in Poland; northern Norway has shown trends towards warmer springs and autumns since 1991, and significant trends towards earlier snowmelt and green-up on test fields in northern Norway.
Authors
Sigridur Dalmannsdottir Marit Jørgensen Marcin Rapacz Liv Østrem Arild Larsen Odd Arne RognliAbstract
No abstract has been registered
Abstract
Europe’s and the World’s northernmost agriculture is very vulnerable to harsh overwintering conditions. It is important from both an economic and societal standpoint to have accurate methods of predicting the severity and impact of the current snow season. Technology has advanced to enable such measurements to be regularly recorded but despite this, a detailed assessment, involving remote sensing , of the impacts of various types of snow season on agricultural yields in northernmost Europe has not previously been undertaken. Here we characterize variation in snow types and concomitant soil frost and ground-ice accumulation at a Norwegian sub-Arctic, maritime-buffered site (Tromsø, Troms County, 69 °N) during the period 1989/90 to 2013/14 and analyse how winter conditions affect agricultural productivity (both measured in the field and using remote sensing). These data were then used to build important predictive modelling approaches. In total, five contrasting types of snow season were identified, from snow-rich with no soil frost and no ground-ice to low snow and considerable soil frost and ground-ice. Conditions of low snow and low soil frost and ground-ice that result from numerous warming events were rare within the time period studied but are predicted to become the dominant snow season type. Agricultural productivity was lowest and claim settlements paid to farmers were highest after winters with high accumulation of plant-damaging, hermetic ground-ice. Deep soil frost per se did not affect primary productivity. Overall, our results together with information from other sources, suggest that icy, low snow conditions are the most challenging of all seasonal types for both the environment and livelihoods in sub-Arctic Norway. Winters with extremely deep snow also cause considerable problems. As winters are expected to warm more than summers, it is likely that the winter climate will become an even stronger regulator of northern primary productivity. To better understand the physical and biological effects of the changing winter climate, there is a requirement for continued and increasing monitoring of winter processes, especially related to frost and ice in the rhizosphere, as this is currently not well covered in national monitoring programs. Continued monitoring will enable further refinement of predictions and will support the better community planning for greatest agricultural benefit. climate change, crop yield, ice, NDVI, plant mortality, snow dynamics, winter climate
Authors
Hanne Sickel Bolette Bele Ragnar Eltun Odd-Arild Finnes Gustav Fystro Knut Hovstad Marit Jørgensen Vibeke Lind Jørgen Todnem Håvard SteinshamnAbstract
No abstract has been registered
Authors
Katarzyna Dabrowska – Zielinska Piotr Goliński Marit Jørgensen Jørgen A.B. Mølmann Gregory Taff Monika Tomaszewska Barbara Golińska Maria Budzynska Martyna GatkowskaAbstract
No abstract has been registered
Editors
Jon SchärerAbstract
High northern latitudes are increasingly exposed to the combination of extreme winter climate and deposition of long-distance dispersed nitrogen pollution. The nature in the north is vulnerable, and these combined pressures may over time drive changes in plant composition and carbon uptake.
Authors
Sigridur Dalmannsdottir Marcin Rapacz Marit Jørgensen Liv Østrem Arild Larsen Rolf Rødven Odd Arne RognliAbstract
The expected temperature rise in late summer/early autumn can change the conditions for acclimation and affect the winter survival of perennial crops. This study examined the effect of the temperature just before the onset of cold acclimation (pre-acclimation) on freezing tolerance of timothy (Phleum pratense L.), perennial ryegrass (Lolium perenne L.) and red clover (Trifolium pratense L.) populations (both cultivars and breeding populations) adapted to either northern or southern parts of Norway. Using phytotron experiments, we studied whether increasing pre-acclimation temperature delays growth cessation, affects photoacclimation and reduces freezing tolerance. Furthermore, we assessed whether these effects were related to the latitudinal adaptation of the plant material. The results showed that a rise in pre-acclimation temperature decreased both cold acclimation capacity and photoacclimation in these species. This affected the freezing tolerance, which was reduced significantly more in northern-adapted population of timothy and perennial ryegrass compared with southern-adapted populations. Red clover was less affected by temperature changes than the grasses.
Abstract
High northern latitudes are increasingly exposed to the combination of extreme winter climate and deposition of long-distance dispersed nitrogen pollution. The nature in the north is vulnerable, and these combined stresses may over time affect the composition of plant species and carbon uptake. How will North-Norwegian ecosystems tolerate unstable winters and nitrogen pollution?
Authors
Katarzyna Dąbrowska-Zielińska Piotr Goliński Marit Jørgensen Jørgen A.B. Mølmann Gregory TaffAbstract
No abstract has been registered
Authors
Håvard Steinshamn Ragnhild Aabøe Inglingstad Dag Ekeberg Jørgen A.B. Mølmann Marit JørgensenAbstract
No abstract has been registered
Authors
Sigridur Dalmannsdottir Marit Jørgensen Marcin Rapacz Liv Østrem Arild Larsen Odd Arne RognliAbstract
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Authors
Marcin Rapacz Åshild Ergon Mats Höglind Marit Jørgensen Barbara Jurczyk Liv Østrem Odd Arne Rognli Anne Marte TronsmoAbstract
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Authors
Laura Kirwan John Connolly Caroline Brophy Ole Hans Baadshaug Gilles Bélanger Allistair Black Tim Carnus Rosemary Collins Jure Cop Ignacio Delgado Alex De Vliegher Anjo Elgersma Bodil Frankow-Lindberg Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Aslaug Helgadottir Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Tor Lunnan Andreas Lüscher Päivi Kurki Claudio Porqueddu Maria Teresa Sebastia Ulrich Thumm David Walmsley John FinnAbstract
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Authors
Marit Jørgensen Kirsten Tørresen Marit Dyrhaug Ingrid Myrstad Jan Svendsen Tone Magnussen Anniken Førde A. DiTommasoAbstract
No abstract has been registered
Authors
Marit Jørgensen Kirsten Tørresen M Dyrhaug I. Myrstad J. Svendsen T. Magnussen A. Førde A. DiTommasoAbstract
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Authors
Marit Jørgensen Kirsten Tørresen Marit Dyrhaug Ingrid Myrstad Jan Svendsen Tone Magnussen Anniken Førde A. DiTommasoAbstract
No abstract has been registered
Authors
E. Sturludottir Caroline Brophy Gilles Bélanger Anne-Maj Gustavsson Marit Jørgensen Tor Lunnan Aslaug HelgadottirAbstract
No abstract has been registered
Authors
John A. Finn Laura Kirwan John Connolly Maria Teresa Sebastia Aslaug Helgadottir Ole Hans Baadshaug Gilles Bélanger Alistair Black Caroline Brophy Rosemary P. Collins Jure Cop Sigridur Dalmannsdottir Ignacio Delgado Anjo Elgersma Michael Fothergill Bodil Frankow-Lindberg An Ghesquiere Barbara Golinska Piotr Golinski Philippe Grieu Anne-Maj Gustavsson Mats Höglind Olivier Huguenin-Elie Marit Jørgensen Zydre Kadziuliene Päivi Kurki Rosa Llurba Tor Lunnan Claudio Porqueddu Matthias Suter Ulrich Thumm Andreas LüscherAbstract
No abstract has been registered
Authors
Håvard Steinshamn Ragnhild Aabøe Inglingstad Andrea Criscione Bernardo Valenti Marit JørgensenAbstract
The objective of the present study was to examine the effect of grazing on different pasture types and hay feeding on dairy goat’s milk casein composition in early and late grazing season. Eighty goats were grouped according to genotype at the αS1-casein locus and number of lactations and randomly divided into two groups (Early and Late) with approximately 8 weeks difference in kidding dates. Goats within each of the two groups were further allocated to four forage treatment groups accounting for genotype and lactation number: R, forest rangeland pasture; C, cultivated pasture; HH, high quality hay; HL, low quality hay. The goats in Early were subjected to forage treatments in early grazing season, while the goats in Late received the forage treatments 8 weeks later. There was a strong effect of genotype but no genotype by diet interaction on casein content and composition. Goats grazing R yielded less milk (1.6 vs. 2.2 kg/d, P<0.001) with higher milk fat content (48 vs. 38 g/kg, P<0.001) than goats on C. Pasture type had no effect on total protein or casein content. However, milk from goats on R compared to C had lower content of αs1-casein (2.57 vs. 3.82 g/L, P<0.01) and κ-casein (4.51 vs. 5.22 g/L, P<0.05) but higher content of β-casein (13.1 vs. 11.7 g/L, P<0.001). Grazing compared to hay gave similar milk yield with higher content of total casein (24.2 vs. 21.0 g/kg, P<0.001), αs2-casein (3.48 vs. 3.04 g/L, P<0.001) and β-casein (12.4 vs. 11.7 g/L, P<0.01). Grazing compared to hay feeding improved the milk casein composition important for cheese making, while cultivated pasture were superior to rangeland.
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Abstract
Traditionally, Norwegian dairy goats graze on diverse forest or alpine rangeland during summer, and these pastures are important both as a feed source, and for keeping the traditional image of goat milk being produced on local “natural” resources. Simultaneously, the grazing goats keep the landscape open. The quality of goat milk often declines during summer, with increased problems with free fatty acids (FFA) in the milk. This seems to coincide with the latter part of the grazing season, when goats generally also are in a later lactation stage, which also can cause problems with FFA. To elucidate the effects of pasture quality on milk production and quality we conducted an experiment where we grouped eighty goats according to genotype and lactation. They were randomly divided into two groups with approximately 8 weeks difference in kidding date and start of feeding experiment in Early (beginning of July) and Late (end of August) grazing season on improved cultivated pasture (PC) or rangeland (PR). Grazing was compared with hay of high (HH) or low (HL) quality. We used n-alkanes and long chained alcohols found in plant waxes as markers to estimate diet composition, and dosed the animals with the even-chained alkane C32 to estimate intake. Grazed plants were analysed also for feed quality. The forage intake was generally high, on average 1.2, 1.9, 2.1 and 1.6 kg DM day-1 per goat for PC, PR, HH and HL, respectively. The intake in the cultivated pasture the diet was predominantly timothy (Phleum pratense) in early season, while meadow fescue (Festuca pratensis) and couch grass (Elytrigia repens) dominated in 2nd period. In the rangeland, the diet was diverse and consisted of ferns, sedges, blueberry (Vaccinium myrtillis) and birch (Betula pubescens) in early summer. In late summer the diet was particularly diverse, coinciding with a general decline in plant quality. R yielded less milk (1.6 vs. 2.2 kg d-1) and lower milk protein content (32 vs. 33 g kg-1), but higher milk fat (48 vs. 38 g kg-1) and DM content (122 vs. 114 g kg-1) than C. Milk content of free fatty acids (FFA) was not affected by pasture type. The effect of pasture type on milk yield and milk constituents were similar in early and late grazing season. Grazing resulted in similar milk yield but higher milk fat (43 vs. 35 g kg-1), protein (32 vs. 30 g kg-1) and DM (118 vs. 107 g kg-1) content and lower content of FFA (0.25 vs. 0.31 mEq L-1) than hay feeding.
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Abstract
The objective of the present study was to examine the effect of grazing on different pasture types and hay feeding on dairy goat milk fatty acid (FA) composition in early and late grazing season. Eighty goats were grouped according to genotype and lactation, and randomly divided into two groups (Early and Late) with approximately 8 weeks difference in mating and kidding dates. Goats within each of the two groups were further allocated to four forage treatment groups: R, forest rangeland pasture; C, cultivated pasture; HH, high quality hay; HL, low quality hay. The goats in Early were subjected to forage treatments in early grazing season, while the goats in Late received the forage treatments 8 weeks later. The most abundant FAs were C16:0 and C18:1c9 followed by C14:0 and C18:0. The milk proportion of the short and medium chained fatty acids (C6:0-C14:0) and C16:0 was higher (P < 0.0001) in Late than in Early grazing season, whilst the proportion of long chained FAs (C18:0, C18:1c9, C18:1t11, C18:2c9, 12, C18:2c9t11 and C18:3c9, 12, 15) were lower (P < 0.001). Goats grazing R yielded less milk (1.5 vs. 2.0 kg/d, P < 0.001) but with higher milk fat content (46 vs. 37 g/kg, P < 0.001) than C. The milk from goats on R had lower (P < 0.01) proportion of medium chained FAs (C10:0-C14:0) and C18:2c9, t11 but higher (P < 0.05) proportion of C18:0, C18:2c9,12 and C20:0 than C. Grazing compared to hay gave milk with lower proportion of medium chained FAs (C12:0-C14:0) and C16:0 but higher proportion of the long chained FAs C18:0, C18:1t11, C18:3c9, 12, C18:2c9, t11, C18:3c9, 12, 15, C20:0 than hay feeding. Higher supply of energy may explain higher proportion of de novo synthesised low and medium chained FA and lower proportion of long chained FA on C than on R, whilst higher supply of FA from mobilized fat may explain higher milk proportion of long chain FA in Early than in late season. Moreover, goats on pasture had likely higher supply of FA from dietary fat, which explain higher milk proportion of the long chained FA than on hay.
Abstract
Norwegian goat milk production is based on summer grazing on diverse forest or alpine rangeland, and the quality of these pastures is important for milk quantity and quality. We used n-alkanes and long chained alcohols found in plant wax as markers to estimate diet composition in goats grazing on a heterogeneous rangeland during two periods in summer; early (beginning of July) and late (end of August). The goats were fitted with GPS collars that recorded their position. Preliminary results show a diverse diet, where ferns, sedges, blueberry (Vaccinium myrtillis) and birch were preferred in early summer. In late summer the diet was particularly diverse, coinciding with a general decline in plant quality.
Abstract
The objective was to examine the effect of pasture type, and of grazing compared with hay feeding, on milk production and quality from dairy goats in early and late grazing season. Eighty goats were grouped according to genotype and lactation, and randomly divided into two groups with approximately 8 weeks difference in kidding date and start of feeding experiment, in Early and Late grazing season. At the start of the feeding experiment the goats were divided into 4 forage-treatment groups: R,forest rangeland pasture; C, cultivated pasture; HH, high quality hay; HL, low quality hay. Group R yielded less milk (1.5 vs. 2.0 kg d–1) and lower milk protein content (32 vs. 33 g kg–1), but higher milk fat (46 vs. 37 g kg–1) and DM content (120 vs. 113 g kg–1) than group C. Free fatty acids (FFA) content in milk was not affected by pasture type. The effects of pasture type on milk yield and milk constituents were similar in early and late grazing season. Grazing resulted in similar milk yield but higher milk fat (42 vs. 34 g kg–1), protein (32 vs. 30 g kg–1) and DM (117 vs. 106 g kg–1) content, and lower content of FFA (0.22 vs. 0.34 mEq L–1) than hay feeding
Abstract
No abstract has been registered
Abstract
Norwegian goat milk production is based on summer grazing on diverse forest or alpine rangeland, and the quality of these pastures is important for milk quantity and quality. We used n-alkanes and long chained alcohols found in plant waxes as markers to estimate diet composition in goats grazing on a heterogeneous rangeland during two periods in summer; early (beginning of July) and late (end of August). Some of the goats were fitted with GPS collars that recorded their position. Preliminary results show a diverse diet, where ferns, sedges, blueberry (Vaccinium myrtillis) and birch (Betula pubescens) were preferred in early summer. In late summer the diet was particularly diverse, coinciding with a general decline in plant quality.
Abstract
No abstract has been registered
Abstract
Scenarios of climate changes indicate longer and more frequent spells of mild weather during winter in northern latitudes. De-hardening in perennial grasses could increase the risk of frost kill. In this study, the resistance to de-hardening of different grass species and cultivars was examined, and whether the resistance changes during winter or between years, was tested. In Experiment 1, two cultivars of timothy (Phleum pratense L.) and perennial ryegrass (Lolium perenne L.) of contrasting winter hardiness were grown under ambient winter conditions, transferred from the field in January and April 2006 to the laboratory for 9 d with controlled de-hardening conditions of 3°C, 9°C and 15°C. The timothy cultivars were tested at 3°C, 6°C and 9°C in a similar experiment (Experiment 2) in January 2007. De-hardening, measured as decrease in frost tolerance (LT50), was less in timothy than in perennial ryegrass and increased with increasing temperatures. The northern winter-hardy cultivar Engmo of timothy de-hardened more rapidly than the less-hardy cultivar Grindstad, but had higher initial frost tolerance in both experiments, whereas there was less difference between cultivars of perennial ryegrass in Experiment 1. Cultivar Grindstad of timothy lost all hardiness in early spring at all temperatures, whereas cultivar Engmo maintained some hardiness at 3°C. Cultivar Engmo de-hardened at a lower rate in 2007 than in 2006, in spite of similar frost tolerance at the start of de-hardening treatment in both years. This indicates that the rate of de-hardening was controlled by factors additional to the initial frost tolerance and that autumn weather conditions might be important for the resistance to de-hardening.
Abstract
Scenarios of climate changes indicate longer and more frequent spells of mild weather during winter in northern latitudes. De-hardening in perennial grasses could increase the risk of frost kill. In this study, the resistance to de-hardening of different grass species and cultivars was examined, and whether the resistance changes during winter or between years, was tested. In Experiment 1, two cultivars of timothy (Phleum pratense L.) and perennial ryegrass (Lolium perenne L.) of contrasting winter hardiness were grown under ambient winter conditions, transferred from the field in January and April 2006 to the laboratory for 9 d with controlled de-hardening conditions of 3°C, 9°C and 15°C. The timothy cultivars were tested at 3°C, 6°C and 9°C in a similar experiment (Experiment 2) in January 2007. De-hardening, measured as decrease in frost tolerance (LT50), was less in timothy than in perennial ryegrass and increased with increasing temperatures. The northern winter-hardy cultivar Engmo of timothy de-hardened more rapidly than the less-hardy cultivar Grindstad, but had higher initial frost tolerance in both experiments, whereas there was less difference between cultivars of perennial ryegrass in Experiment 1. Cultivar Grindstad of timothy lost all hardiness in early spring at all temperatures, whereas cultivar Engmo maintained some hardiness at 3°C. Cultivar Engmo de-hardened at a lower rate in 2007 than in 2006, in spite of similar frost tolerance at the start of de-hardening treatment in both years. This indicates that the rate of de-hardening was controlled by factors additional to the initial frost tolerance and that autumn weather conditions might be important for the resistance to de-hardening.
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Authors
Vibeke Lind Jan Berg Lars Olav Eik Jørgen A.B. Mølmann Espen Haugland Marit Jørgensen Margrethe HerslethAbstract
Many consumers perceive lamb meat from mountain pastures to be of superior quality, a quality that may be altered if lambs are kept for a longer period on cultivated pastures before slaughtering. The objective of this experiment was to compare sensory profile and fatty acid composition in meat from lambs slaughtered directly from unimproved mountain pastures with meat from lambs raised on unimproved mountain pastures and fattened on biodiverse cultivated pastures for 26, 39 and 42 days before slaughtering. The experiment was conducted at two different locations in Norway in 2006 and 2007, with a total of 124 Norwegian Crossbred Sheep lambs. Loin samples of M. Longissimus dorsi from lambs above a body weight of 40 kg were selected and analysed for sensory attributes. Fatty acid composition was determined in the subcutaneous fat over the Longissimus dorsi. Small but significant differences were found in hardness, tenderness, fattiness, metallic and rancid flavour, and in polyunsaturated fatty acids. This indicates that to a small extent pre-slaughter fattening on cultivated pastures alters meat characteristics. (C) 2009 Elsevier Ltd. All rights reserved.
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Authors
Laura Kirwan Andreas Lüscher Maria Teresa Sebastia J Finn Rosemary P Collins C Porqueddu Helga Helgadottir O. H. Baadshaug Caroline Brophy C Coran Sigridur Dalmannsdottir I Delgado A. Elgersma Mick Fothergill Bodil Frankow-Lindberg B Golinski P Grieu A.M. Gustavsson Mats Höglind O Huguenin-Elie C Iliadis Marit Jørgensen Z Karyotis Tor Lunnan M Malengier V Meyer D Nyfeler P Nykanen-Kurki J Parente H J Smit U Thumm John ConnollyAbstract
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