Torfinn Torp

Seniorrådgiver

(+47) 466 27 834
torfinn.torp@nibio.no

Sted
Ås - Bygg H7

Besøksadresse
Høgskoleveien 7, 1433 Ås

Sammendrag

High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2 + T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2 + T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2 + T2 in oat grains. Our data show that adequate predictions of the risk of HT2 + T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2 + T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2 + T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2 + T2 accumulation in oat grains. Our data indicated that HT2 + T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.

Sammendrag

Monitoring changes in forest height, biomass and carbon stock is important for understanding the drivers of forest change, clarifying the geography and magnitude of the fluxes of the global carbon budget and for providing input data to REDD+. The objective of this study was to investigate the feasibility of covering these monitoring needs using InSAR DEM changes over time and associated estimates of forest biomass change and corresponding net CO2 emissions. A wall-to-wall map of net forest change for Uganda with its tropical forests was derived from two Digital Elevation Model (DEM) datasets, namely the SRTM acquired in 2000 and TanDEM-X acquired around 2012 based on Interferometric SAR (InSAR) and based on the height of the phase center. Errors in the form of bias, as well as parallel lines and belts having a certain height shift in the SRTM DEM were removed, and the penetration difference between X- and C-band SAR into the forest canopy was corrected. On average, we estimated X-band InSAR height to decrease by 7 cm during the period 2000–2012, corresponding to an estimated annual CO2 emission of 5 Mt for the entirety of Uganda. The uncertainty of this estimate given as a 95% confidence interval was 2.9–7.1 Mt. The presented method has a number of issues that require further research, including the particular SRTM biases and artifact errors; the penetration difference between the X- and C-band; the final height adjustment; and the validity of a linear conversion from InSAR height change to AGB change. However, the results corresponded well to other datasets on forest change and AGB stocks, concerning both their geographical variation and their aggregated values.

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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.

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The effects of a commercial seaweed (SW) product and extracts collected from wild SWs in the Northern Norway on cultivable commensal intestinal bacterial groups isolated from Norwegian White sheep ewes were studied in vivo and in vitro. Bacterial counts from faeces from the ewes fed with supplement which contained SW meal throughout the entire indoor winter period had significantly lower lactic acid bacteria (LAB) counts (P ≈ .05). The screening of extracts from red and brown SWs showed that a number of the organic extracts had an inhibitory effect on the growth of the two Enterococcus sp. isolates. The results indicate that Ascophyllum nodosum supplementation reduces LAB counts in the ewes and the lambs, and that extracts from this SW have an inhibitory effect on the growth of Enterococcus sp. isolates.

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More sustainable production of high-quality, nutritious food is of worldwide interest. Increasing nutrient recycling into food systems is a step in this direction. The objective of the present study was to determine nitrogen (N) fertiliser effects of four waste-derived and organic materials in a cropping sequence of broccoli, potato and lettuce grown at two latitudes (58° and 67° N) in Norway during three years. Effects of anaerobically digested food waste (AD), shrimp shell (SS), algae meal (AM) and sheep manure (SM) at different N application rates (80 and 170 kg N ha–1 for broccoli, and 80 and 60 kg N ha–1 for potato and lettuce, respectively) and residual effects were tested on crop yield, N uptake, N recovery efficiency (NRE), N balance, N content in produce, mineral N in soil, product quality parameters and content of nitrate in lettuce. Mineral fertiliser (MF) served as control. Effects on yield, N uptake, NRE, N balance and product quality parameters could to a great extent be explained by estimated potentially plant-available N, which ranked in the order of AD>SS>SM>AM. Results for crops fertilised with AD and SS were not significantly different from MF at the same N application rate, while AM, in agreement with its negative effect on N mineralisation, gave negative or near-neutral effects compared to the control. No residual effect was detected after the year of application. The results showed that knowledge about N dynamics of relevant organic waste-derived fertilisers is necessary to decide on the timing and rate of application.

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During the last ten years, Norwegian cereal grain industry has experienced large challenges due to Fusarium spp. and Fusarium mycotoxin contamination of small-grained cereals. To prevent severely contaminated grain lots from entering the grain supply chain, it is important to establish surveys for the most prevalent Fusarium spp. and mycotoxins. The objective of our study was to quantify and calculate the associations between Fusarium spp. and mycotoxins prevalent in oats and spring wheat. In a 6-year period from 2004-2009, 178 grain samples of spring wheat and 289 samples of oats were collected from farmers’ fields in South East Norway. The grains were analysed for 18 different Fusarium-mycotoxins by liquid chromatography – mass spectrometry. Generally, the median mycotoxin levels were higher than reported in Norwegian studies covering previous years. The DNA content of Fusarium graminearum, Fusarium culmorum, Fusarium langsethiae, Fusarium poae and Fusarium avenaceum were determined by quantitative PCR. We identified F. graminearum as the main deoxynivalenol (DON) producer in oats and spring wheat, and F. langsethiae as the main HT-2 and T-2-toxins producer in oats. No association was observed between quantity of F. graminearum DNA and quantity of F. langsethiae DNA nor for their respective mycotoxins, in oats. F. avenaceum was one of the most prevalent Fusarium species in both oats and spring wheat. The following ranking of Fusarium species was made based on the DNA concentrations of the Fusarium spp. analysed in this survey (from high to low): F. graminearum = F. langsethiae = F. avenaceum > F. poae > F. culmorum (oats); F. graminearum = F. avenaceum > F. culmorum > F. poae = F. langsethiae (spring wheat). Our results are in agreement with recently published data indicating a shift in the relative prevalence of Fusarium species towards more F. graminearum versus F. culmorum in Norwegian oats and spring wheat.

Sammendrag

High concentrations of the mycotoxin deoxynivalenol (DON), produced by Fusarium graminearum have occurred frequently in Norwegian oats recently. Early prediction of DON levels is important for farmers, authorities and the Cereal Industry. In this study, the main weather factors influencing mycotoxin accumulation were identified and two models to predict the risk of DON in oat grains in Norway were developed: (1) as a warning system for farmers to decide if and when to treat with fungicide, and (2) for authorities and industry to use at harvest to identify potential food safety problems. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). A mathematical model was developed and used to estimate phenology windows of growth stages in oats (tillering, flowering etc.). Weather summarisations were then calculated within these windows, and the Spearman rank correlation factor calculated between DON-contamination in oats at harvest and the weather summarisations for each phenological window. DON contamination was most clearly associated with the weather conditions around flowering and close to harvest. Warm, rainy and humid weather during and around flowering increased the risk of DON accumulation in oats, as did dry periods during germination/seedling growth and tillering. Prior to harvest, warm and humid weather conditions followed by cool and dry conditions were associated with a decreased risk of DON accumulation. A prediction model, including only pre-flowering weather conditions, adequately forecasted risk of DON contamination in oat, and can aid in decisions about fungicide treatments.

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A controlled climatic chamber microcosm experiment was conducted to examine how light affects the hourly sporulation pattern of the beneficial mite pathogenic fungus Neozygites floridana during a 24 h cyclus over a period of eight consecutive days. This was done by inoculating two-spotted spider mites (Tetranychus urticae) with N. floridana and placing them on strawberry plants for death and sporulation. Spore (primary conidia) discharge was observed by using a spore trap. Two light regimes were tested: Plant growth light of 150 μmol m−2 s−1 for 12 h supplied by high pressure sodium lamps (HPS), followed by either; (i) 4 h of 50 μmol m−2 s−1 light with similar HPS lamps followed by 8 h darkness (full HPS light + reduced HPS light + darkness) or (ii) 4 h of 50 μmol m−2 s−1 red light followed by 8 h darkness (full HPS light + red light + darkness). A clear difference in hourly primary conidia discharge pattern between the two different light treatments was seen and a significant interaction effect between light treatment and hour in day during the 24 h cycle was observed. The primary conidia discharge peak for treatment (ii) that included red light was mainly reached within the red light hours (19:00–23:00) and the dark hours (23:00–07:00). The primary conidia discharge peak for treatment (i) with HPS light only was mainly reached within the dark hours (23:00–07:00).

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The density and diversity of springtails (Collembola) in the upper soil layer (0–3.8 cm) were studied in a perennial grass-clover ley in NW Norway during April–June 2012. The study was part of a field experiment comparing yields and soil characteristics after application of non-digested slurry (NS) versus anaerobically digested slurry (DS) from dairy cows. In total for three sampling dates, 39 species of springtails were identified. In the Control plots receiving no manure, the density level was around 30 000 individuals (ind.) m−2 throughout the whole season. Three days after slurry application (40 t ha−1), the density of springtails had dropped significantly; from 55 214 to 7410 ind. m−2 in the NS treatment and from 41 914 to 10 260 ind. m−2 in the DS treatment. After 7 weeks the densities had increased again to 54% and 38% of the initial levels in NS and DS treatments, respectively. The springtails were divided into two ecological groups based on morphology and colour. The epigeic group comprised surface-dwelling species with eye organs and pigmentation. The endogeic group comprised soil-dwelling species lacking eye organs and pigmentation, and generally with shorter extremities than those found in the epigeic group. The negative effect of manure application on density was more severe and long-lasting in the epigeic than in the endogeic group. This effect was similar for both manure types. One species (Parisotoma notabilis) comprised 50% of the epigeic population, while three Mesaphorura spp. and Stanaphorura lubbocki comprised half the endogeic population. In general, the community structure, described by the relative abundance of each species, was more affected by manure application in the epigeic than in the endogeic group. Hence, slurry application seemed to affect surface-dwelling species more negatively than soil- dwelling species, even within the small sampling depth used here. The density of endogeic species seemed to recover faster than the density of the epigeic species. A simplified classification of epigeic and endogeic springtails, based on the presence or absence of pigmentation and eyes, may be useful in studies of soil springtails where identification of the actual species is not the primary purpose.

Sammendrag

Aim: The objective was to assess the nitrogen provided to following crops by peas and fava beans, with varying legume residue incorporation and use of cover crops. Meth: Organic field trial, ‘spilt-split plot design’ with 4 blocks. Whole plots (spring 2014) had legumes (pea or faba beans), and sub plots (autumn 2014) had 4 autumn soil treatments with combinations of legume residue incorporation and cover crop. The sub-sub plots (spring 2015) were with and without additional manure fertilization. Res: The root biomass of both legume pre cops had equal nitrogen (N) concentration, but total root biomass was twice as high for fava beans as for peas (5.08 vs. 2.41 kg m-2). Fava bean pre crop with biomass incorporation without cover crop gave the highest broccoli yield (4.10 t ha-1) compared with pea pre crop with biomass incorporation and no cover crop (2.44 t ha -1). Also the last crop in the rotation, lettuce, had 94% higher yield after fava beans (6.6 t ha-1) compared to peas (3.4 t ha-1). Rye as cover crop efficiently assimilated and conserved N during winter, shown by a 4 to 5 fold reduction in soil NO3-N, and nearly 2 fold reduction in soil N-min levels, compared to open soil. Additional manure application affected crop yield, with 3 and 2 fold increase in broccoli and lettuce respectively. Conc: Fava beans as pre crop resulted in higher yields of broccoli and lettuce the following seasons, compared to peas. This was explained twice as much root biomass for that crop.

Sammendrag

A meta-analysis based on experiments in organically cultivated grasslands in Norway was conducted to quantify the effects of management factors on herbage yield and feed quality. A dataset was collected that included 496 treatment means from experiments in five studies carried out at eight locations with the latitude range of 58.8 to 69.6 N between 1993 and 2010. We tested the effect of harvesting system (two vs. Three cuts annually), plant developmental stage at the first cut, growth period (temperature sum) and the herbage clover proportion. Plant maturity at the first cut and herbage clover proportion explained to a large extent herbage yield and quality of the first cut and annual yield. The timing of the first cut influenced also the yield and herbage quality of the second cut. The analysis confirmed the importance of legumes performance for herbage yield and quality from grasslands in organic production. Estimated annual herbage DM yield harvested at standardized plant development stage and at average clover proportion was 9%higher in the two—compared to the three-cut system. The crude protein concentration and in vitro dry matter digestibility was 17 and 3 % higher and the NDF concentration 7 % lower in the annual herbage from the three-cut than from the twocut system, respectively. The empirical equations developed in this study may be applied to explore different options for grassland management as basis for ration and production planning and in scenario analysis of economic performance of individual and model farms. The equations do also reveal in numeric terms the tradeoffs in management practice between high yields, yield digestibility, NDF and crude protein content in organic forage production relying on red clover N2 fixation as the engine in the system.

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Embodied energy in barns is found to contribute to about 10–30% of total energy use on dairy farms. Nevertheless, research on sustainability of dairy farming has largely excluded consideration of embodied energy. The main objectives of this study were to apply an established model from the residential and commercial building sector and estimate the amount of embodied energy in the building envelopes on 20 dairy farms in Norway. Construction techniques varied across the buildings and our results showed that the variables which contributed most significantly to levels of embodied energy were the area per cow-place, use of concrete in walls and insulation in concrete walls. Our findings are in contrast to the assumption that buildings are similar and would show no significant differences. We conclude that the methodology is sufficiently flexible to accommodate different building design and use of materials, and allows for an efficient means of estimating embodied energy reducing the work compared to a mass material calculation. Choosing a design that requires less material or materials with a low amount of embodied energy, can significantly reduce the amount of embodied energy in buildings.

Sammendrag

I forbindelse med godkjenning av plantevernmidler ønsker Mattilsynet mer kunnskap om pollinerende insekter kan bli eksponert for neonikotinoider i konsentrasjon som kan gi negative effekter. Imidakloprid som er ekstremt giftig for bier, er godkjent for bruk i veksthus og er funnet i planteavfall (høyeste funn 7 μg/g tørrvekt TS) og avrenning fra avfall. Mattilsynet ønsket å avdekke om plantevernmiddelrester i planteavfall og kompost av planteavfall kan opptre i blomstrende kulturplanter i konsentrasjoner som kan medføre uheldig eksponering av pollinerende insekter. Vekstforsøk med bringebær og solsikke - gode trekkplanter for pollinerende insekter - ble gjennomført i veksthus ved Bioforsk Vest Særheim. Plantene ble dyrket i vekstrenner med torv tilsatt Confidor med aktiv substans imidakloprid, nektar og pollen ble samlet inn og analysert for imidakloprid ved Bioforsk Plantehelse og plantevern. Studien viste at laveste og høyeste imidakloprid-konsentrasjon i nektar og pollen fra bringebær og solsikke som vokste i veksttorv med en imidakloprid-konsentrasjon rundt 28 μg/g TS, var 16,7 - 131,8 ng/g og 25,0 - 26,4 ng/g (bringebær) og 59,0- 109,6 ng/g og 28,5 - 79,3 ng/g (solsikker). Med antagelsen at det er lineær sammenheng mellom konsentrasjonsnivå i vekstmedie og i nektar og pollen vil vi, ut fra denne studien, kunne anslå at høyeste beregnet konsentrasjon i nektar vil være 33,0 ng/g for bringebær og 27,4 ng/g for solsikke hvis de hadde vokst i planteavfall/kompost med en imidaklorpid-konsentrasjon på 7 μg/g TS (høyeste målte konsentrasjon i avfall fra veksthus). Tilsvarende beregnet antatt høyeste konsentrasjon i pollen vil være 6,6 ng/g og 19,8 ng/g for henholdsvis bringebær og solsikke.

Sammendrag

I forbindelse med godkjenning av plantevernmidler ønsker Mattilsynet mer kunnskap om pollinerende insekter kan bli eksponert for neonikotinoider i konsentrasjon som kan gi negative effekter. Imidakloprid som er ekstremt giftig for bier, er godkjent for bruk i veksthus og er funnet i planteavfall (høyeste funn 7 μg/g tørrvekt TS) og avrenning fra avfall. Mattilsynet ønsket å avdekke om plantevernmiddelrester i planteavfall og kompost av planteavfall kan opptre i blomstrende kulturplanter i konsentrasjoner som kan medføre uheldig eksponering av pollinerende insekter. Vekstforsøk med bringebær og solsikke - gode trekkplanter for pollinerende insekter - ble gjennomført i veksthus ved Bioforsk Vest Særheim. Plantene ble dyrket i vekstrenner med torv tilsatt Confidor med aktiv substans imidakloprid, nektar og pollen ble samlet inn og analysert for imidakloprid ved Bioforsk Plantehelse og plantevern. Studien viste at laveste og høyeste imidakloprid-konsentrasjon i nektar og pollen fra bringebær og solsikke som vokste i veksttorv med en imidakloprid-konsentrasjon rundt 28 μg/g TS, var 16,7 - 131,8 ng/g og 25,0 - 26,4 ng/g (bringebær) og 59,0- 109,6 ng/g og 28,5 - 79,3 ng/g (solsikker). Med antagelsen at det er lineær sammenheng mellom konsentrasjonsnivå i vekstmedie og i nektar og pollen vil vi, ut fra denne studien, kunne anslå at høyeste beregnet konsentrasjon i nektar vil være 33,0 ng/g for bringebær og 27,4 ng/g for solsikke hvis de hadde vokst i planteavfall/kompost med en imidaklorpid-konsentrasjon på 7 μg/g TS (høyeste målte konsentrasjon i avfall fra veksthus). Tilsvarende beregnet antatt høyeste konsentrasjon i pollen vil være 6,6 ng/g og 19,8 ng/g for henholdsvis bringebær og solsikke.

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The use of artificial freezing tests, identification of biomarkers linked to or directly involved in the low-temperature tolerance processes, could prove useful in applied strawberry breeding. This study was conducted to identify genotypes of diploid strawberry that differ in their tolerance to low-temperature stress and to investigate whether a set of candidate proteins and metabolites correlate with the level of tolerance. 17 Fragaria vesca, 2 F. nilgerrensis, 2 F. nubicola, and 1 F. pentaphylla genotypes were evaluated for low-temperature tolerance. Estimates of temperatures where 50 % of the plants survived (LT50) ranged from −4.7 to −12.0 °C between the genotypes. Among the F. vesca genotypes, the LT50 varied from −7.7 °C to −12.0 °C. Among the most tolerant were three F. vesca ssp. bracteata genotypes (FDP821, NCGR424, and NCGR502), while a F. vesca ssp. californica genotype (FDP817) was the least tolerant (LT50 −7.7 °C). Alcohol dehydrogenase (ADH), total dehydrin expression, and content of central metabolism constituents were assayed in select plants acclimated at 2 °C. The LT50 estimates and the expression of ADH and total dehydrins were highly correlated (r adh = −0.87, r dehyd = −0.82). Compounds related to the citric acid cycle were quantified in the leaves during acclimation. While several sugars and acids were significantly correlated to the LT50 estimates early in the acclimation period, only galactinol proved to be a good LT50 predictor after 28 days of acclimation (r galact = 0.79). It is concluded that ADH, dehydrins, and galactinol show great potential to serve as biomarkers for cold tolerance in diploid strawberry.