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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.

2024

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Within the EU Horizon project OPTAIN (OPtimal strategies to reTAIN and re-use water and nutrients in small agricultural catchments across different soil-climatic regions in Europe, optain.eu) project, the effects of Natural/Small Water Retention Measures (NSWRMs) on water regime, soil erosion and nutrient transport are evaluated at both, catchment- and field-scales for present and future climate conditions. Our goal is to perform an integrated, model-based assessment of the effectiveness of NSWRMs at field scale and cross-validated these results from those obtained from the catchment-scale modelling. The field-scale assessment is based on the adaptation of the SWAP mathematical model to seven pilot sites across three European biogeographical regions and on combined NSWRM – projected climate scenario analyses. The scenarios are designed to evaluate the efficiency and potential of different natural/small water retention measures in improving soil water retention and reducing flash floods and the loss of soil and nutrients under changing climate conditions. We present the harmonized SWAP modelling workflow and the combined scenario analyses, including the implementation of various in-field measures in the SWAP model. Examples of model calibration, validation and scenario results for selected pilot sites will be given.

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Soil management strategies involving the application of organic matter (OM) inputs (crop residues, green and livestock manure, slurry, digestate, compost and biochar) can increase soil carbon storage but simultaneously lead to an increase in non-CO2 greenhouse gas (GHG) emissions such as N2O. Although multiple meta-analyses have been conducted on the topic of OM input impacts on GHG, none has focused specifically on European arable soils. This study plugs this gap and can assist policymakers in steering European agriculture in a more sustainable direction. The objective of this meta-analysis was to quantify how OM inputs of different nature and quality, but also the application strategy, can mitigate soil N2O emissions in different pedoclimatic conditions in Europe. We quantitatively synthesised the results of over 50 field experiments conducted in 15 European countries. Diverse arable crops, mainly cereals, were cultivated in monoculture or in crop rotations on mineral soils. Cumulative N2O emissions were monitored during periods of 30–1070 days in treatments, which received OM inputs, alone or in combination with mineral N fertiliser; and in controls fertilised with mineral N. The overall effect of OM inputs had a slight tendency to reduce N2O emissions by 10% (n = 53). With the increasing carbon-to-nitrogen ratio of the OM inputs, this mitigation effect became more pronounced. In particular, compost and biochar significantly reduced N2O emissions by 25% (n = 6) and 33% (n = 8) respectively. However, their effect strongly depended on pedoclimatic characteristics. Regarding the other types of OM inputs studied, a slight N2O emission reduction can be achieved by their application alone, without mineral N fertiliser (by 16%, n = 17). In contrast, their co-application with mineral N fertiliser elevated emissions to some extent compared to the control (by 14%, n = 22). We conclude that amongst the seven OM inputs studied, the application of compost and biochar are the most promising soil management practices, clearly demonstrating N2O emission reduction compared to mineral N fertiliser. In contrast, other OM inputs had a small tendency to mitigate N2O emissions only when applied without mineral N fertiliser.

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The brown marine macroalga Alaria esculenta contains phlorotannins as polyphenolic compounds in its cell walls. This study aimed to understand their antioxidant effects on preserving the lipids in fillets of freshly-slaughtered farmed Atlantic salmon (Salmo salar). First, soluble phlorotannins were extracted from wild-grown population of A. esculenta in North Norway (Bodø) using solid/liquid extraction. A small-scale solid/liquid extraction (15 mg mL−1) with 70% acetone showed that 84% of total soluble phlorotannins (25.10 mg g−1 dry weight) were extracted after the first out of four extraction steps. In a large-scale extraction (3 mg 400 mL−1), the contents of soluble phlorotannins and the DPPH-based antioxidant capacities (measured as IC50) in 70% acetone- and water-based crude extracts were similar. Water is preferred extraction solvent for the following experiment because it complies with food safety standards, may minimise work procedures and is in accordance with the principles of Green Chemistry. Secondly, the antioxidant properties of the soluble phlorotannins were tested through incubating salmon fillets (Norwegian Quality Cuts) in water-based extracts. After six days of storage on ice, the peroxide value of Alaria-treated fillets was lower compared to the control (without Alaria-extract), while the p-anisidine and free fatty acid values remained unchanged. This indicates the phlorotannins’ inhibitory effect on the formation of primary rather than secondary lipid oxidation products. This study demonstrated that the antioxidant properties of the soluble phlorotannins extracted from A. esculenta using water can preserve the nutritional value of salmon fillets to extend the seafood’s shelf-life.

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Livestock summer grazing in mountains and forests in Norway is generally considered beneficial to biodiversity. In this study we investigated if this is the case for cattle in boreal production forest. We collected biodiversity data on field layer vegetation, floral resources and flower-visiting insects in young spruce plantations that were planted 2–10 years ago. We picked young spruce plantations inside and outside well-established cattle grazing areas. On each plantation, we sampled fenced and unfenced plots (20 * 20 m each). This study design allowed us to investigate long-term effects of cattle grazing as well as short-term effects of excluding cervids only and short-term effects of excluding cervids and cattle. Long-term cattle grazing reduced the abundance of woody plants and reduced the abundance of flowers. Excluding cervids for two summers led to reduced height of woody plants (shrubs and heather) and to increased flower abundance. In contrast, excluding cervids and cattle for two summers led to increased height of graminoids, herbs and woody plants, to higher abundance of graminoids, higher flower abundance and higher abundance of flower-visiting insects. In conclusion, cattle affected the studied system in different ways and to a larger extent than native cervids. Our study shows that we must be careful when inferring results from cattle grazing studies on grasslands to forest ecosystems. As this study documents a negative effect of cattle on floral resources and flower-visiting insects, and we currently are facing a global pollination crisis, a careful consideration of the current practice of cattle grazing in boreal forest might be needed.

Abstract

Climate change causes far-reaching disruption in nature, where tolerance thresholds already have been exceeded for some plants and animals. In the short-term, deer may respond to climate through individual physiological and behavioral responses. Over time, individual responses can aggregate to the population level and ultimately lead to evolutionary adaptations. Because responses by deer to climate change may take many paths - both positive and negative - it is generally difficult to predict outcomes. Here we take the first step to understanding these complexities by systematically synthesizing the literature (published 2000-2022) regarding direct effects of temperature, rainfall and snow on deer inhabiting boreal and temperate regions of the northern hemisphere. Our review (based on N= 219 papers) shows that while many deer populations will likely benefit from warmer winters, hotter and drier summers may exceed their physiological tolerances, causing northwards shifts in distributional ranges. We found support for deer expressing both phenotypic and behavioral plasticity in response to climate variability at different temporal and spatial scales. We identified 20 general patterns, among which some illustrate antagonistic pathways, suggesting that detrimental effects will cancel out some of the benefits of climate change. Our findings highlight the importance of local variables for any predictions of future responses by a given deer population. We identified several knowledge gaps, such as studies regarding the potential impact on these animals of extreme weather events, snow type and wetter autumns.

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Body condition score (BCS) has been a useful tool in estimating the health of cattle for many years now. This categorical metric requires experienced observers to visually inspect cows and assess body fat deposits regularly via a time consuming, subjective process. Low cost RGB+depth cameras have been used alongside machine learning algorithms in the past and have shown great promise, however, more advanced techniques are projected to yield better performance. In this work, a vision transformer (ViT) is pretrained using a recently developed self-supervised pretraining method, masked image modeling, and then fine-tuned on RGB+depth BCS data with the objective of improving performance. Model accuracy was found to be highly dependent on dataset curation, ranging from 64% to 92% accuracy. These discrepancies are attributed to non-unique data in the training and test splits and an inherently unbalanced dataset, both of which are discussed in detail. It is recommended that engineers and animal scientists collaborate more closely, as certain details related to dataset curation are critical to thoroughly assess performance and robustness of automated methods for BCS determination.

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Studies have shown that extended wilting of grass before ensiling can improve the metabolizable protein (MP) value of the grass silage, both from increased rumen microbial crude protein (MCP) yield and ruminally undegraded crude protein (RUP). We hypothesised that extending the wilting of grass before ensiling can increase milk and milk protein production in dairy cows. Consequently, increased silage MP can reduce the need for MP in concentrate, estimated as amino acids absorbed in the small intestine (AAT20). To test this, a continuous feeding experiment was conducted, with 48 early- to mid-lactation Norwegian Red dairy cows. Treatments were 2 wilting levels of grass silages: 260 vs. 417 g dry matter (DM) per kg, and 2 qualities of concentrates differing in MP, in a 2 × 2 factorial arrangement (n = 12). The concentrates were low MP (LMP); 104 g AAT20/kg DM, and high MP (HMP); 123 g AAT20/kg DM, supplied at 8.75 kg DM/cow per day. The cows had ad libitum access to the grass silages. The experiment lasted for 11 weeks. The first 2 weeks, where cows received identical diets, were used as the covariate period. Those data together with data collected the last 4 weeks were used for statistical evaluation of treatments. Increasing DM concentration in silage reduced lactic acid, ammonia nitrogen and proportion of methionine in the grass silage, while it increased residual water-soluble carbohydrates, pH, proportion of aspartic acid and rumen degradability of NDF. There was no difference between treatments in daily silage DM intake (13.1 kg), milk yield (30.2 kg) or milk composition. However, feeding HMP increased urea and uric acid in urine, and urea in blood plasma, thereby reduced N efficiency. No major differences were found for rumen pH, or purine derivatives to creatinine index in urine, as indication for MCP. There was significantly more histidine in blood plasma when cows were fed HMP concentrate. In conclusion, increased DM concentration in silage and HMP concentrate did not increase milk production or milk protein yield in this study.

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The substitution of chemical nitrogen (N) fertilizer with organic fertilizer (organic substitution, OS) is increasingly applied in crop production, due to its environmentally friendly characteristics, low price, and high crop and soil improvement efficacies. Here, we studied the effects of chemical N fertilizer with organic fertilizer treatment at different proportions (no organic substitution (NOS), 20% (OS-20), 40% (OS-40), 60% (OS-60), 100% (OS-100), and 200% (OS-200, double the organic fertilizer application amount of OS-100) on the yield and quality of apples in the Shanxi Province of China. The results revealed that, compared to the NOS, the total apple yields of OS treatments, especially the OS-60 and OS-100 treatments, decreased. However, all OS treatments, except OS-200, increased the yield of large-sized fruits (transverse diameter ≥ 85 mm) and the mean mass of apple fruits, and significantly decreased yield of small-sized fruits (transverse diameter < 75 mm). All OS treatments, especially OS-40, promoted the total sugar and vitamin C (Vc) contents and fruit hardness of apples, and OS-40, OS-60, and OS-200 resulted in significantly decreased titratable acid contents in apples. The influence of organic substitutions on soil quality was further investigated in a two-year field experiment. The results showed that the influence of organic substitution on soil chemical properties differed between the two years. Notably, 40% OS increased the soil organic carbon (SOC) content and the C/N ratio in the upper 20 cm of the soil in both years. Additionally, OS treatments reduced the residual nitrate (NO3−)-N (RN) content in deep soil layers, suggesting that OS has the potential to alleviate N leaching. Moreover, redundancy analysis (RDA) of the soil, fruit yield, and fruit quality parameters revealed that the SOC content in the 0–20 cm soil layer and the RN content in the 0–100 cm soil layer had the greatest impact on the fruit quality and yield variables, respectively. This study showed that the proper substitution (40%) of chemical N fertilizer with organic fertilizer could improve the yield of large-sized fruits, the mean mass and fruit quality of apples, and soil chemical properties. Our study will provide a basis for rational organic substitution in apple orchards.