Organic Cropping Systems Stability, Resilience and Profitability At the USDA-ARS Beltsville Farming Systems Project.

The USDA-ARS Beltsville Farming Systems Project (FSP), initiated in 1996, consists of three organic and two conventional cropping systems.  The FSP is one of only five long-term agricultural research (LTAR) sites in the US that includes both organic and conventional no-till systems and is the only LTAR site that includes three organic systems that differ in crop rotation length and complexity.  Results to date indicate that increasing crop rotation length and complexity reduce production challenges in organic systems.  For example, corn yield was 10 and 30% greater in a six-year rotation (Org6) that includes summer annual (corn, soybean), winter annual (winter wheat), and herbaceous perennial (alfalfa for three years) cash crops than in a three-year rotation (Org3) that includes only summer and winter annual cash and cover crops, and a two-year rotation (Org2) that includes only summer annual cash crops and winter annual cover crops, respectively.  Improvements were related to greater N availability and lesser weed competition as crop rotation complexity increased.  Increasing crop rotation length and complexity also reduced predicted soil erosion, N₂O emissions, economic risk, animal manure inputs and soil P loading.  Predicted soil erosion was lower in an organic (Org3) than in a conventional chisel till system (CT) but conventional no-till (NT) provides considerable soil erosion control compared to either of the tilled systems.  Initial results indicate Org3 has lower global warming potential (GWP) due to greater C sequestration and lower energy use than the conventional systems.  However, N₂O emissions in Org3 seem to be greater than in the conventional systems.  Additional longitudinal data from the first 17 years of the study will be presented to assess the stability and resilience of crop yield and economic performance, addressing these issues in the context of soil quality in the various cropping systems.