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.
2008
Abstract
About Norwegian lunch packages. Their history and current schemes for fruit and milk.
Abstract
The content of sulphur (S) in grassland on 27 Norwegian organic farms with dairy or sheep production was investigated in 2001 and 2002. The forage content of S was below the norms (2 g S kg DM-1) for both plants and animals in a large proportion of the samples. The average S content in forage at dairy farms was 1.4 g S kg DM-1 and at sheep farms 1.5 g. Even on grasslands with low plant S content (<1 g S kg DM-1), S-fertilization did not increase yields and increased the plants’ S content only very slightly. No indications of S deficiency were observed on the dairy farms. For one sheep farm with a forage S content of 1.1 ± 0.1g S kg DM-1, brittle and short winter wool was reported.
Abstract
From 2002 to 06, the annual dropout rate of certified organic farmers averaged 7.3%. A project was started in 2007 to explore farmer’s reasons for opting out of certified organic production. Important factors seem to be public regulations including standards for organic farming, agronomy, economy, and farm exit. While many organic farmers with relatively small holdings have opted out, farmers with more land and larger herds tend to convert to organic agriculture. The trend towards larger-scale farms in organic than in conventional agriculture, encouraged by the design of the organic farming payments, challenges the organic principles of diversity and fairness. Means should be considered to ensure that small organic enterprises are also economically viable.
Abstract
The aim of the present work was to study to what extent N in mulched green manure herbage contributes to spring barley grain yield the subsequent year. The green manure herbage was either chopped and left on stubble (GML) or removed (GMR). On silty clay loam with spring incorporated green manure the subsequent barley grain yield was 10% higher with GML than with GMR. The additional grain N yield of 4 kg ha-1 with GML corresponded to only 3 % of N in above-ground green manure biomass. On loamy soil with late autumn incorporated green manure the treatments did not affect the grain yield the subsequent year. How large part of the N that was lost through leaching or gaseous emissions and how large part that was built into soil organic matter was not measured. However, this investigation confirms that potential N losses from mowed green manure might be large. Alternative ways of using the herbage should be found.
Authors
Jens Kværner Petter SnilsbergAbstract
No abstract has been registered
Abstract
Recent in situ 13C studies suggest that lignin is not stabilised in soil in its polymerised form. However, the fate of its transformation products remains unknown. The objective of the present research was to provide the first comprehensive picture of the fate of lignin-derived C across its transformations processes: (1) C remaining as undecomposed lignin molecules, (2) C in newly formed humic substances, i.e. no longer identifiable as lignin-polymer C, (3) C in microbial biomass, (4) C mineralised as CO2, and (5) dissolved organic C. To achieve this objective, we designed an incubation experiment with 13C-labelled lignin where both elementary and molecular techniques were applied. Lignin was isolated from 13C labelled maize plants (13C-MMEL) and incubated in an agricultural soil for 44 weeks. Carbon mineralisation and stable isotope composition of the released CO2 were monitored throughout the incubation. Microbial utilisation of 13C-MMEL was measured seven times during the experiment. The turnover rate of the lignin polymer was assessed by 13C analysis of CuO oxidation products of soil lignin molecules. After 44 incubation weeks, 6.0% of initial 13C-MMEL carbon was mineralised, 0.8% was contained in the microbial biomass, and 0.1% was contained in dissolved organic C form. The compound-specific 13C data suggest that the remaining 93% were overwhelmingly in the form of untransformed lignin polymer. However, limited transformation into other humic substances potentially occurred, but could not be quantified because the yield of the CuO oxidation method proved somewhat variable with incubation time. The initial bacterial growth yield efficiency for MMEL was 31% and rapidly decreased to plateau of 8%. A two-pool first-order kinetics model suggested that the vast majority (97%) of MMEL lignin had a turnover time of about 25 years, which is similar to field-estimated turnover times for soil-extractable lignin but much longer than estimated turnover times for fresh plant-residue lignin. We conclude that natural lignin structures isolated from plants are rather unreactive in soil, either due to the lack of easily available organic matter for co-metabolism or due to enhanced adsorption properties. The data also suggest that fairly undecomposed lignin structures are the main reservoir of lignin-derived C in soils.
Abstract
No abstract has been registered
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No abstract has been registered
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No abstract has been registered
Abstract
No abstract has been registered