GREENHOUSE GAS FLUXES IN AGRICULTURAL SOILS UNDER ORGANIC AND NON-ORGANIC MANAGEMENT

Farming practices are known to exert strong control over the soils’ function to act as sources or sinks for greenhouse gases (GHG). This paper deals with the outcome of a recent meta-analysis based on the evaluation of 19 published long-term farming system comparisons. It provides a comprehensive data base regarding GHG fluxes from soils under organic and non-organic management. There is scientific evidence for lower nitrous oxide emissions from organically managed soils when scaled to the area. However, further data from farming system comparisons are required, particularly from long-term GHG measurements covering several cropping seasons or ideally entire crop rotations. This enables closing knowledge gaps concerning N fluxes and pools under organic management as well as the formation of the new soil ecosystem (soil quality) equilibrium after implementing organic practices. Substantial reductions of nitrous oxide emissions as well as enhancement of methane uptake can be reached by consequent application of “good agricultural practice” and simple adoptions of soil management, forming together a balanced set of GHG mitigation mechanisms. In addition we provide first GHG flux data from the well-known DOK farming system trial in Therwil/CH and the role of microbial communities driving soil functioning.