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). A recent meta-analysis based on the evaluation of 74 published long-term system comparisons provides a comprehensive data base regarding soil organic matter development (SOM) and C sequestration potential of organic systems (Gattinger et al., 2012). Furthermore, the impact of sustainable land management practices including organic farming on soil carbon was also analysed for agricultural systems under Mediterranean climate (Aguilera et al., 2013. A comprehensive literature review on GHG (= non-CO2) fluxes in agricultural soils under organic and non-organic management is missing. The generally lower N input level in organic agriculture compared to non-organic supports the expectation of lower nitrous oxide emissions and enhanced methane uptake in organically managed soils. There are some indications that organic agriculture leads to less soil-born greenhouse gas emissions than conventional agriculture (Niggli et al., 2009), but this phenomenon has, however, never been investigated systematically. Thus a comprehensive literature review followed by a meta-analysis was conducted to compare non-CO2 GHG emissions from soils under organic and non-organic management. In addition we provide first GHG flux data from the well-known DOK farming system trial in Therwil/CH.