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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.

2021

Abstract

Self-sufficiency with feed (SSF) is a basic principle in organic animal production. The current regulations do not impose strict requirements for SSF at farm level, but further restrictions are expected in future. The aim of the present work was to quantify SSF on a range of organic dairy farms in Norway and study farmers’ strategies to produce milk with a high degree of SSF. Nine farms were selected for interview and data collection. On farm level, the proportion of SSF varied between 66 and 99 %. SSF increased to 88-100 % when expressed on national level. Land area is among the limiting factors for famers to reach higher SSF while maintaining the milk production level. A lower proportion of concentrates in the diet seems to have as strong impact on SSF as using own cereals and protein crops as feed, but milk production per total feed production area was highest for the latter. The farmers’ goals and actions are important driving forces to develop more SSF in dairy production systems.

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Abstract

Organic agriculture is acquiring increased attention in Armenia with numerous projects and initiatives prioritizing production of ecologically clean agricultural products. Application of organic fertilizers is one of the key factors supporting sustainable organic production of fruits and vegetables, which requires knowledge of fertilization regimes adapted to crop types for achieving optimum productivity. The present study evaluates the effect of the organic fertilizer “Bioklad” (Bioklad Ltd.) on growth and development of strawberry plantlets. Three concentrations of the organic fertilizer, 1:400, 1:200 and 1:100 dilutions of the concentrate were tested. Plantlets of the cultivar ‘Sonata’ were grown for nine weeks in pots under controlled conditions in a phytotron. Yield, biomass and total phenolic content were not significantly different between Bioklad application treatments. Nevertheless, the Bioklad at the intermediate dilution 1:200 was most optimal for strawberry growth. The analysis of chemical composition of leaves indicated that nitrogen content was higher in plants grown at the lowest dilution (1:100) of Bioklad. In addition, plantlets had the lowest phenolic content at this treatment. Based on the presented results of Bioklad’s effect on strawberry plantlets growth, cost/value insight of this organic fertilizer has been estimated.

Abstract

Inclusion of clover in grasslands increases functional diversity, N yield and forage quality and has been advocated for mitigating nitrous oxide (N2O) emissions. However, boreal grass-clover leys often show poor winter survival with considerable aboveground losses of nitrogen (N) and carbon (C). Little is known about how these losses affect off-season N2O emissions. Here we report field experiments over two winters, conducted at two coastal locations in Western and Northern Norway. N2O emissions were measured in plots with 0, 30 and 100% red (T. pretense) and white clover (T. repens) in a timothy - meadow fescue mixture. Overwinter N loss from the sward was quantified by comparing N contents in roots, stubble and herbage in autumn and spring. Additional treatments were removal of above-ground biomass in autumn and soil compaction. Off-season N2O emissions correlated positively with estimated overwinter N loss from herbage, which in turn depended on the fraction of clover in the ley. Pure grass leys emitted less N2O than leys that contained clover. Corrected for background emissions from pure grass, up to 13% of the above-ground N loss was emitted as N2O–N when clover was grown in pure stand. This fraction was much smaller, however, when clover was grown in mixture with grass (1.9 ± 0.9%), suggesting reassimilation of inorganic N. Indeed, we found significant increases in root and stubble N in mixtures throughout winter. Removal of above-ground biomass in autumn appeared to reduce the sward's ability to retain N throughout winter, and hence had no or a stimulating effect on N2O emissions. Soil compaction increased off-season N2O emissions 1.3–1.6-fold. Our results show that boreal grass-clover leys can be a significant source of N2O during winter, intricately controlled by loss and reassimilation of N. This underscores the importance of off-season plant-soil management for reducing the greenhouse gas (GHG) footprint of animal production in high latitude ecosystems.