Tor Arvid Breland

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The effect of roots on microbial growth and N immobilization was investigated in a pot experiment with barley, Italian ryegrass, and white clover. We used a silty subsoil with a low soil organic matter content (0.16%C and 0.012%N), which allowed us to measure N immobilization as an increase in total soil organic N (planted versus unplanted). At sampling,(More)
Knowledge about the mineralization dynamics of plant material added to soil is essential in order to predict potential effects on off-season N losses and N uptake by subsequent crops. Among the factors that may influence mineralization is the degree of contact with the soil matrix, as determined by the extent of mixing when plant material is incorporated.(More)
BACKGROUND AND AIMS White clover (Trifolium repens) is, due to nitrogen (N) fixation, important to the N dynamics of several northern temperate agroecosystems. This study aimed at monitoring growth and death of major white clover plant organs to assess their potential contribution to within-season N input and risk of off-season N losses. METHODS White(More)
Modeling the C and N dynamics during decomposition of plant residues depends on robust estimation of the litter pool partitioning (LPP) of residues, i.e. the fraction of their C and N allocated to rapidly and slowly decomposing pools. We searched for ways to estimate LPP by analyzing data on C and N mineralization during decomposition of 60 widely different(More)
Organic vegetable production attempts to pursue multiple goals concerning influence on environment, production resources, and human health. In areas with limited availability of animal manure, there is a need for considering various off-farm nutrient resources for such production. Different organic and waste-derived fertilizer materials were used for(More)
Predictive models of the temporal mineralization pattern of organic residues may help in development of strategies to synchronize N mineralization with the crop demand and minimize off-season losses. In the present investigation, two double first-order models with temperature as a driving variable were tested against data on decomposition and N(More)
Engineering an ontology on organic agriculture and agroecology: the case of the Organic.Edunet project Abstract Education is essential to raise public awareness on organic agriculture and agroecology (OA & AE). The EU funded project Organic.Edunet will provide an online, freely-available portal where learning contents on OA & AE can be published and(More)
We applied a mechanistic ecosystem model to investigate the production and environmental performances of (1) current agricultural practice on two fields of a stockless organic cereal farm in southeast Norway and (2) alternative cereal-ley rotations and plowing time scenarios. Scenarios were simulated using historic weather data and a climate change(More)
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