Organic soybean and corn production in Wisconsin has rapidly increased to meet demand of the expanding organic dairy industry (USDA-ERS, 2006). A major challenge that organic row crop growers face is the intensive tillage needed for successful weed management (Posner et al., 2008), spurring interest by growers in improving weed management techniques (Walz, 1999). The use of a rye cover crop to facilitate no-till organic soybean production may improve weed management for organic growers, and provide additional ecosystem services including reduced soil erosion and runoff, increased soil organic matter and water infiltration, and trapping of excess nitrogen. This organic no-till rye mulch system has been limited in part due to uncertainty regarding the reliability of mechanical methods of terminating the cover crop, difficulty in establishing soybeans in the rye residue (Williams et al., 2000; Reddy et al., 2003), and the potential risk of competition between the rye cover crop and soybeans for soil moisture and nutrients resulting in reduced yields and economic returns (De Bruin et al., 2005; Westgate, 2005).
We conducted research to determine some of the agronomic, economic, and environmental risks associated with the use of winter rye cover crop in no-till organic soybean production systems. Our objectives were to determine the effect of rye management (plowing, crimping, and mowing), and soybean planting date (mid-May or early June) on soil moisture availability, soybean stand establishment, weed suppression, and soybean yield. Treatment effects on economic gross margins, soil loss, and soil quality were also predicted.