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.
2021
Abstract
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Authors
Ingunn Øvsthus Kristian Thorup-Kristensen Randi Seljåsen Hugh Riley Peter Dörsch Tor Arvid BrelandAbstract
Mechanistic models are useful tools for understanding and taking account of the complex, dynamic processes such as carbon (C) and nitrogen (N) turnover in soil and crop growth. In this study, the EU-Rotate_N model was first calibrated with measured C and N mineralization from nine potential fertilizer resources decomposing at controlled soil temperature and moisture. The materials included seaweeds, wastes from the food industry, food waste anaerobically digested for biogas production, and animal manure. Then the model’s ability to predict soil and crop data in a field trial with broccoli and potato was evaluated. Except for seaweed, up to 68% of added C and 54–86% of added N was mineralized within 60 days under controlled conditions. The organic resources fell into three groups: seaweed, high-N industrial wastes, and materials with high initial content of mineral N. EU-Rotate_N was successfully calibrated for the materials of industrial origin, whereas seaweeds, anaerobically digested food waste and sheep manure were challenging. The model satisfactorily predicted dry matter (DM) and N contents (root mean square; RMSE: 0.11–0.32) of the above-ground part of broccoli fertilized with anaerobically digested food waste, shrimp shell pellets, sheep manure and mineral fertilizers but not algal meal. After adjusting critical %N for optimum growth, potato DM and N contents were also predicted quite well (RMSE: 0.08–0.44). In conclusion, the model can be used as a learning and decision support tool when using organic materials as N fertilizer, preferably in combination with other models and information from the literature.
Authors
Mette Thomsen Tor J. Johansen Eldrid Lein Molteberg Anne-Berit Wold Arne Hermansen Anne-Kristin Løes Hugh RileyAbstract
Several factors may define storability in root crops. In the following paper, preliminary results are presented from two experiments performed to test factors affecting storage quality of carrot. The study have focused on 1) soil loosening/soil compaction and 2) different cultivars of carrot and root age considered by the length of the growing period. The results so far indicate that the soil compaction had few effects on storability of carrot, but did seem to negatively affect the length of the carrot. Soil loosening reduced the occurrence of liquorice rot caused by Mycocentrospora acerina. Large differences were found in storability between the ten tested carrot cultivars and length of growing period tended to be negatively correlated to storability. We conclude that a number of precautions in carrot production may increase storability and thus economic performance.
Abstract
Leaf blotch diseases (LBD), such as Septoria nodorum bloch (Parastagnospora nodorum), Septoria tritici blotch (Zymoseptoria tritici) and Tan spot (Pyrenophora tritici-repentis) can cause severe yield losses (up to 50%) in Norwegian spring wheat (Triticum aestivum) and are mainly controlled by fungicide applications. A forecasting model to predict disease risk can be an important tool to optimize disease control. The association between specific weather variables and the development of LBD differs between wheat growth stages. In this study, a mathematical model to estimate phenological development of spring wheat was derived based on sowing date, air temperature and photoperiod. Weather factors associated with LBD severity were then identified for selected phenological growth stages by a correlation study of LBD severity data (17 years). Although information regarding host resistance and previous crop were added to the identified weather factors, two purely weather-based risk prediction models (CART, classification and regression tree algorithm) and one black box model (KNN, based on K nearest neighbor algorithm) were most accurate to predict moderate to high LBD severity (>5% infection). The predictive accuracy of these models (76–83%) was compared to that of two existing models used in Norway and Denmark (60 and 61% accuracy, respectively). The newly developed models performed better than the existing models, but still had the tendency to overestimate disease risk. Specificity of the new models varied between 49 and 74% compared to 40 and 37% for the existing models. These new models are promising decision tools to improve integrated LBD management of spring wheat in Norway.
Authors
Pia Heltoft Thomsen Gudni Thorvaldsson Anne Mette Dahl Jensen Tatsiana Espevig Karin Juul Hesselsøe Wendy Marie Waalen Torben Kastrup Petersen Trond Olav Pettersen Jan Tangsveen Per Sørensen Tania Gneist Bjarni Hannesson Kristine Sundsdal Trygve S. AamlidAbstract
Seed mixtures with a nurse grass that germinates quickly at low soil temperatures can be an option for faster establishment of Agrostis stolonifera (AS) putting greens after winter damage. From 2015 to 2018 Poa trivialis (PT) ‘Dark Horse’ and Lolium perenne (LP) ‘Chardin’ were evaluated as nurse grasses in comparison with pure AS ‘Independence’ at two experimental sites in each of the two major climatic zones of the Nordic countries. Poa annua (PA) ‘Two‐Putt’ was also included as a nurse grass in the northern zone. As an overall trend, establishment was faster with AS+LP than with AS+PT and AS+PA, which in turn had faster establishment than pure AS. In the northern zone, AS+PT produced better turf quality than pure AS in the seeding year and year after and tended to be superior even on average for the entire trial period (mean value 6.0 vs. 5.8 for pure AS, 5.3 for AS+LP, and 4.6 for AS+PA; scale 1–9 where 9 is the highest quality). In the same zone, AS+PT also suffered less overall winter damage than the other combinations and was less infected with microdochium patch than pure AS. In the southern zone, PT and especially LP were far more persistent than in the northern zone and compromised turfgrass quality compared with pure AS. In conclusion, we recommend PT as a nurse grass for faster establishment of AS putting in the northern zone, but not in the southern zone where AS should rather be seeded in a pure stand.
2020
Abstract
To achieve a complete organic value chain, we need organic seed from cultivars adapted to organic growing. A separate breeding for organic growing is difficult to achieve in small markets. Many breeding goals are equal for organic and conventional cereals, and cultivars failing to qualify as a commercial variety for conventional growing may possibly perform well in organic growing, with different regimes of fertilisation and plant protection. A field trial was conducted over 2 years to compare 25 cultivars of spring wheat, ranging from one land race and some old varieties released between 1940 and 1967, to modern market varieties and breeding lines. Grain yield, agronomic characteristics and grain and flour quality, including mineral content, were recorded. The performance of the 20 most interesting cultivars in artisan bread baking was measured, as were sensory attributes in sourdough bread from six cultivars. Modern varieties and breeding lines gave higher yields and had larger kernels, better grain filling, higher falling numbers and higher SDS-sedimentation volumes compared with old cultivars. The old cultivars, on average, had higher concentrations of minerals, although the growing site had a strong effect on mineral concentrations. Bread from modern cultivars performed best in a baking test. Several sensory attributes such as juiciness, chew resistance, firmness, acid taste and vinegar odour varied significantly between the six tested cultivars. Land races and old varieties have an important cultural value, and many consumers are willing to pay a premium price for such products. This will be required since yield levels are often considerably lower, especially with humid weather conditions at harvest.
Abstract
Many Norwegian consumers eat more red meat than is recommended by the Government. Of the protein currently consumed, 75% is of animal origin. Natural conditions in Norway favour the production of meat, dairy and seafood but high-protein plants can also be grown in the country. This study analysed the environmental impact of growing turnip rapeseed (Brassica rapa) and rapeseed (Brassica napus) and the processing of rapeseed into dietary oil and press cake. The results were then compared with some common animal protein food sources. Impacts were calculated for 24 impact indicators. The climate impact of dried seeds was 1.19 kg CO2-eq/kg, for rape oil—3.0 kg CO2-eq/kg and for rapeseed press cake—0.72 kg CO2-eq/kg. The environmental impact of rapeseed production is higher than in most other countries, predominantly due to lower yields. Press cake from rapeseed could be a valuable source of protein in foods. In Norway, the environmental impacts of this material (climate impact—2.5 kg CO2-eq/kg protein) are at the same level as other plant protein sources, but far lower than some of the most common animal protein sources (climate impact—16–35 kg CO2-eq/kg protein). When comparing the impacts while taking nutrient content into account, these differences remained the same. Improvements in the environmental performance of oilseed and its products can be achieved both by improving yields through better agronomic practices and increasing the proportion of winter rapeseed.
Abstract
Microbes are central drivers of soil processes and in-depth knowledge on how agricultural management practices effects the soil microbiome is essential in the development of sustainable food production systems. Our objective was therefore to explore the long-term effects of organic and conventional cropping systems on soil bacterial and fungal quantity, their community structures and their combined function. To do so, we sampled soil from a long-term experiment in Southeast Norway in 2014, 25 years after the experiment was established, and performed a range of microbial analyses on the samples. The experiment consists of six cropping systems with differences in crop rotations, soil tillage, and with nutrient application regimes covering inorganic fertilizers, cattle slurry (both separately and combined with inorganic fertilizers) and biogas residues from digested household biowaste. The quantity of soil microbes was assessed by extraction of microbial C and N and by analysis of soil DNA (bacterial 16S rRNA, and fungal rRNA internal transcribed spacer region). The structures of the microbial communities were determined and assessment of relatedness of bacterial and fungal communities was done by the unweighted pair group method. Estimates of richness and diversity were based on numbers of unique operational taxonomic units from DNA sequencing and the function of the microbial assembly was measured by means of enzyme assays. Our results showed that production systems including leys had higher microbial biomass and higher numbers of bacterial and fungal gene copies than did systems with cash crops only. A cropping system which appeared to be particularly unfavourable was a reference-system where stubble, roots and exudates were the single source of organic material. Production system significantly affected both bacterial and fungal community structures in the soil. Systems including leys and organic fertilization had higher enzyme activities than did systems with cash crops only. An inclusion of ley in the rotation did not, however, increase either microbial richness or microbial diversity. In fact, the otherwise suboptimal reference-system appeared to have a richness and diversity of both bacteria and fungi at levels similar to those of the other cropping systems, indicating that the microbial function is largely maintained under less favourable agricultural treatments because of the general resilience of soil microorganisms to various stresses. Neither disturbance through tillage nor the use of chemical fertilizer or chemical plant protection measures seemed as such to influence soil microbial communities. Thus, no differences between conventional and organic farming practices as such were found. We conclude that the choice of agricultural management determines the actual microbial community structure, but that biodiversity in general is almost unaffected by cropping system over many years. Adequate addition of organic material is essential to ensure a properly functioning microbial ensemble and, thus, to secure soil structure and fertility over time.
Abstract
Optimizing phosphorus (P) application to agricultural soils is fundamental to crop production and water quality protection. We sought to relate soil P tests and P sorption characteristics to both crop yield response to P application and environmentally critical soil P status. Barley (Hordeum vulgare L.) was grown in pot experiments with 45 soils of different P status. Half the pots were fertilized at 20 kg P ha−1, and half received no P. Soils were extracted with ammonium lactate, sodium bicarbonate (Olsen P), dilute salt (0.0025 M CaCl2), and diffusive gradient in thin films. Soil adsorption coefficients were determined using the Freundlich isotherm equation, and the degree of P saturation was determined from both oxalate and ammonium lactate extracted Fe, Al, and P. All soil P analyses showed a nonlinear and significant relationship with yield response to P application, and all analyses manifested a threshold value above which no P response was observed. For the commonly used ammonium lactate test, inclusion of Al and Fe improved prediction of plant‐available soil P. The threshold for yield response coincided with the environmentally critical values determined from the degree of P saturation. Results support the conclusion that soil P levels for which no P application is needed also have elevated risk of P loss to runoff.