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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2020

Abstract

Forskningsformidling til ungdom 13-19 år. Et nettbasert undervisningstilbud som bruker naturforskning til å fremme ungdoms miljøbevissthet og interesse for vitenskap.

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Abstract

Four raspberry cultivars were grown at two different latitudes namely in Geisenheim (DE, 49°60’N; 7°57’E) and in Kapp (NO, 60°42’N; 10°52’E) to investigate the impact of these growing sites on primary and secondary fruit chemical ingredients in the 2017 season. Fruits were harvested at two picking dates each with three field replications. Contents of °Brix, glucose, fructose, sucrose, organic acids, ascorbic acid, polyols, total polyphenols, and anthocyanins were analyzed in the fruits. The geographic growing sites, which in this case is more than10 latitudes between HGU in Germany and NIBIO in Norway, has partly no, partly significant effects on the primary and secondary ingredients of the investigated raspberry cultivars. In respect to the created data set, temperatures shortly before or at the picking dates were not considered. It may be expected that temperatures at harvest have an effect on the fruit ingredients and therefore on a further classification of the samples.

Abstract

Recycling of waste fractions from farms and greenhouses might reduce environmental pollution. However, recycling of nutrient solution in greenhouse is risky due to danger of disease spread. Nitrification bacteria can be used for aerobic conversion of ammonia to nitrate in organic waste and may function as stable microbial community protecting against pathogen attacks by enhancing induced systemic resistance of plants. We developed a hydroponic cultivation system “Organoponics” allowing growth of tomato plant on organic fertilizer with recirculation of nutrient solution. Liquid by-product of biogas production has been used as organic fertilizer. A moving-bed bioreactor was integrated in the system for aerobic nitrification of ammonia. Influence of fertilizer composition (organic, mineral matching organic, standard mineral) and addition of plant growth promoting bacteria on biomass distribution, tomato fruit quality were investigated. Plants grown on organic fertilizer were more generative with largest root index. They also produced fruits with significantly larger average size along whole cluster. Addition of the bacteria to root rhizosphere improved yield and quality parameters of plants received organic fertilization and negatively affected the same parameters in plants received mineral fertilization.

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Abstract

In a number of pathosystems involving the powdery mildews (Erysiphales), plant stress is associated with decreased disease susceptibility and is detrimental to pathogen growth and reproduction. However, in strawberry, anecdotal observations associate severe powdery mildew (Podosphaera aphanis) with water stress. In a 2017 survey of 42 strawberry growers in Norway and California, 40 growers agreed with a statement that water-stressed strawberry plants were more susceptible to powdery mildew compared with nonstressed plants. In repeated in vitro and in vivo experiments, we found that water stress was consistently and significantly unfavorable to conidial germination, infection, and increases in disease severity. Deleterious effects on the pathogen were observed from both preinoculation and postinoculation water stress in the host. Soil moisture content in the range from 0 to 50% was correlated (R2 = 0.897) with germinability of conidia harvested from extant colonies that developed on plants growing at different levels of water stress. These studies confirm that P. aphanis fits the norm for biotrophic powdery mildews and hosts under stress. Mild water stress, compared with a state of optimal hydration, is likely to decrease rather than increase susceptibility of strawberry to P. aphanis. We believe it is possible that foliar symptoms of leaf curling due to diffuse and inconspicuous infection of the lower leaf surfaces by P. aphanis could easily be mistakenly attributed to water stress, which we observed as having a nearly identical leaf curling symptom in strawberry.

Abstract

After harvest, vegetables go from storing assimilates to break down of assimilates and it is of crucial importance to slow down this process. Controlling the pre-storage period may contribute to maintain high quality in root vegetables during long-term storage. The aim of this 2-years study was to investigate the effect of seven different pre-storage strategies (direct to 0°C vs. down 1°C per day vs. 0.2°C temperature reduction per day and wound healing at 10°C with low/high humidity) on root storability in four cultivars of carrot (Daucus carota subsp. sativus) stored in 2016/2017/2018, swede (Brassica napus) in 2017/2018 and celeriac (Apium graveolens var. rapaceum) in 2017/2018. Mass loss and disease incidences were determined during and after long-term storage (6-7 month) in small-scale stores. Wound healing with low humidity resulted in larger mass loss than the other preharvest strategies in carrot and celeriac. In carrot, slow temperature reduction (0.2°C per day) also resulted in larger mass loss than the other strategies. Significantly higher numbers of infected roots, dominated by licorice rot (Mycocentrospora acerina), tip rot and gray mold (Botrytis cinerea), occurred in carrots stored at 0°C immediately compared to roots with a period of wound healing and slow temperature decline. In celeriac, the incidence of gray mold (Botrytis cinerea) and licorice rot (Mycocentrospora acerina) were significantly reduced with wound healing at low humidity. Storage quality of swede was not affected by pre-storage strategies. This study shows that prestorage strategies affect mass loss and disease incidence in celeriac and carrot during and after long-term storage.

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Abstract

Meat demand is likely influenced by the birth cohort and age of the individual. In this study, we examine the demand for beef, pork, poultry, and other meat in the United States using the 1984–2012 Consumer Expenditure Survey and the almost ideal demand system with the incorporation of age, period, and cohort (APC) effects. We find that the model with APC effects performs better than the models without APC effects. The results indicate that cohorts born in earlier time periods are expected to purchase significantly less poultry compared to cohorts born in later time periods, when they are measured at the same age. Over the life cycle, purchase of poultry is expected to increase with age while the opposite is true for red meat. We also find that the own‐price elasticity for beef is highest among the products examined, while the own‐price elasticity for other meat is lowest and the inclusion of APC effects increases the absolute value of the own‐price elasticities for beef, pork, and poultry, but reduces the own‐price elasticity for other meat. Our forecasts indicate that the aggregate poultry purchase will continue to increase until 2022, while the aggregate purchase of red meat will slightly increase until 2017, but will either decrease or stay at same level from year 2017 to 2022.

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Abstract

Spruce-fir-beech mixed forests cover a large area in European mountain regions, with high ecological and socio-economic importance. As elevation-zone systems they are highly affected by climate change, which is modifying species growth patterns and productivity shifts among species. The extent to which associated tree species can access resources and grow asynchronously may affect their resistance and persistence under climate change. Intra-specific synchrony in annual tree growth is a good indicator of species specific dependence on environmental conditions variability. However, little attention has been paid to explore the role of the inter-specific growth asynchrony in the adaptation of mixed forests to climate change. Here we used a database of 1790 tree-ring series collected from 28 experimental plots in spruce-fir-beech mixed forests across Europe to explore how spatio-temporal patterns of the intra- and inter-specific growth synchrony relate to climate variation during the past century. We further examined whether synchrony in growth response to inter-annual environmental fluctuations depended on site conditions. We found that the inter-specific growth synchrony was always lower than the intra-specific synchrony, for both high (inter-annual fluctuations) and low frequency (mid- to long-term) growth variation, suggesting between species niche complementarity at both temporal levels. Intra- and inter-specific synchronies in inter-annual growth fluctuations significantly changed along elevation, being greater at higher elevations. Moreover, the climate warming likely induced temporal changes in synchrony, but the effect varied along the elevation gradient. The synchrony strongly intensified at lower elevations likely due to climate warming and drying conditions. Our results suggest that intra- and inter-specific growth synchrony can be used as an indicator of temporal niche complementarity among species. We conclude that spruce-fir-beech mixtures should be preferred against mono-specific forests to buffer climate change impacts in mountain regions.