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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.

2019

Abstract

Agroforestry can be defined as sustainable and multifunctional land-use systems where trees are managed together with agricultural crops or livestock on the same piece of land. In the northern periphery area, agroforestry has a long history with woodland grazing, reindeer husbandry and gathering of different non-wood forest resources as herbs, mushrooms and berries. Traditional agroforestry has gradually disappeared during the 20th century with the intensification of agriculture and forestry. Currently agroforestry systems are gaining new interest, not only from farmers but also from politicians, as this practice can possibly contribute to a more sustainable way of agricultural production. In the northern periphery area, the benefits of agroforestry practices can be manifold not only promoting traditional practices, but also novel systems with the use of new technology. In addition, agroforestry has environmental benefits as a method for conservation and enhancement of biodiversity, improved nutrient cycling, and water quality. Soil humus layer will also increase with several agroforestry systems leading to carbon sequestration. Here we present an overview of agroforestry practices in the Nordic countries and the use of non-wood forest resources with the emphasis on wild berries.

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Abstract

Liming of acidic soils has been suggested as a strategy to enhance N2O reduction to N2 during heterotrophic denitrification, and mitigate N2O emission from N fertilised soils. However, the mechanisms involved and possible interactions of key soil parameters (NO3− and O2) still need to be clarified. To explore to what extent soil pH controls N2O emissions and the associated N2O/(N2O + N2) product ratio in an acidic sandy soil, we set-up three sequential incubation experiments using an unlimed control (pH 4.1) and a limed soil (pH 6.9) collected from a 50-year liming experiment. Interactions between different NO3− concentrations, N forms (ammonium- and nitrate) and oxygen levels (oxic and anoxic) on the liming effect of N2O emission and reduction were tested in these two sandy soils via direct N2 and N2O measurements. Our results showed 50-year liming caused a significant increase in denitrification and soil respiration rate of the acidic sandy soil. High concentrations of NO3− in soil (>10 mM N in soil solution, equivalent to 44.9 mg N kg−1 soil) almost completely inhibited N2O reduction to N2 (>90%) regardless of the soil pH value. With decreasing NO3− application rate, N2O reduction rate increased in both soils with the effect being more pronounced in the limed soil. Complete N2O reduction to N2 in the low pH sandy soil was also observed when soil NO3− concentration decreased below 0.2 mM NO3−. Furthermore, liming evidently increased both N2O emissions and the N2O/(N2+N2O) product ratio under oxic conditions when supplied with ammonium-based fertiliser, possibly due to the coupled impact of stimulated nitrification and denitrification. Overall, our data suggest that long-term liming has the potential to both increase and decrease N2O emissions, depending on the soil NO3− level, with high soil NO3− levels overriding the assumed direct pH effect on N2O/(N2+N2O) product ratio.