Hopp til hovedinnholdet

Publikasjoner

NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2020

Til dokument

Sammendrag

Growth of CO2 concentration level has strong interactions with forests. Forests are able to sequester carbon (C) through photosynthesis and can help to mitigate the effects of climate warming, as well as to reduce the CO2 concentration in the atmosphere. Drought and other extreme weather conditions play a key role in ecosystem functioning and the C-cycle. The eddy covariance (EC) method can be used to better understand forest ecosystems CO2 exchange by directly measuring net carbon and water fluxes. In our study, EC results for measurement of fluxes between the atmosphere and forest canopy are reported for the study period from May to August 2018 in Järvselja, Estonia. Stand-replacing disturbance (clear-cutting) took place in April 2013. The young forest stand is dominated by Norway spruce (Picea abies) and birch (Betula spp.). Findings so far include (1) a C-budget for the study period that showed a slight C-sink status; (2) net ecosystem exchange (NEE) was −0.0084 µmol m−2 s−1 indicating C-uptake during the measurement period; (3) in May, June, July and August, NEE was −0.027, −0.015, 0.001 and 0.006 µmol m−2 s−1, respectively; (4) NEE fluxes are lower in drought conditions and are affected by temperature that averaged 15 °C.

Sammendrag

Coccidiosis is a serious disease caused by Eimeria spp. in young lambs in Norway. Re-sistance against anticoccidial chemicals has been demonstrated in conventional sheep farm-ing. In organic farming we are looking for natural plant sources to increase animal health and welfare. Condensed tannins (CT) have showed effect against coccidia in several trials. Extract from Norwegian spruce bark (Picea abies), a waste product from the wood industry, was shown to contain CT in a Norwegian study. In our trial we tested the effect of bark extract from Norwegian spruce against Eimeria spp in young lambs. The extract was prepared by hot water extraction followed by evaporation and freeze drying. 24 naïve lambs were randomly grouped, 16 of them were inoculated with 100 000 Eimeria oocysts each for three days at 3 weeks of age, and eight of the 16 were treated with bark extract for 12 successive days post infection. The CTg per lamb per day correspond to 0.05% BMW. A control group of eight lambs was not infected or treated. Individually faeces samples were collected and analysed for faecal score and oocysts. Clinically observations and weight gain were measured. In this trial the bark extract was found to have a significant effect on the development of Eime-ria spp. oocysts in the lambs (p<0,001). The extract was given by a stomach tube, and had a negative effect on the lambs appetite as long as it was administered.

Til dokument

Sammendrag

To respect the Paris agreement targeting a limitation of global warming below 2°C by 2100, and possibly below 1.5 °C, drastic reductions of greenhouse gas emissions are mandatory but not sufficient. Large‐scale deployment of other climate mitigation strategies are also necessary. Among these, increasing soil organic carbon (SOC) stocks is an important lever because carbon in soils can be stored for long periods and land management options to achieve this already exist and have been widely tested. However, agricultural soils are also an important source of nitrous oxide (N2O), a powerful greenhouse gas, and increasing SOC may influence N2O emissions, likely causing an increase in many cases, thus tending to offset the climate change benefit from increased SOC storage. Here, we review the main agricultural management options for increasing SOC stocks. We evaluate the amount of SOC that can be stored as well as resulting changes in N2O emissions to better estimate the climate benefits of these management options. Based on quantitative data obtained from published meta‐analyses and from our current level of understanding, we conclude that the climate mitigation induced by increased SOC storage is generally overestimated if associated N2O emissions are not considered but, with the exception of reduced tillage, is never fully offset. Some options (e.g, biochar or non‐pyrogenic C amendment application) may even decrease N2O emissions.

Sammendrag

Perennial versus short term (<3 years) grass vegetation cover is likely to have considerable differences in root density and thus carbon (C) inputs to soil. Carbon inputs are important to maintain soil organic carbon (SOC) and may even increase it. In Norway and Scandinavia, the SOC content in soil is often higher than in other parts of Europe, due to the cold climate and high precipitation (i.e. slower turnover rates for soil organic matter) and a dominance of animal production systems with a large amount of grassland. Here we aimed to evaluate differences in SOC content, down to 60 cm depth, of a long-term grassland (without ploughing for decades) and a short-term grassland (frequently renewed by ploughing) under contrasting climate, soil and management conditions. Quantification of SOC was carried out on three long-term experimental sites on an extended latitude gradient in West and North Norway. The samples were taken from 4 depth increments (0-5, 5-20, 20-40 and 40-60 cm) in treatments that have not been ploughed for at least 43 years, and in treatments that were ploughed every third year until 2011. Preliminary results suggest that there is no significant difference in SOC storage down to 60 cm between long-term and short-term grasslands.