Organic soybean production: challenges and perspectives of an increasing trend

Annual organic soybean [Glycine max (L.) Merr.] production in the U.S. has risen to more than 60,000 ha in less than 10 yr. This presentation reviews current organic soybean research being conducted in Iowa and elsewhere throughout the U.S. It examines challenges that producers must deal with and shares our perspectives on this increasing trend. Critical challenges associated with organic soybean production include weed control, crop rotation, bean leaf beetles (Ceratoma trifurcata) - primarily as vectors for the seed-staining bean pod mottle virus (BPMV) and other seed-staining fungi such as Cercospora kikuchii and Fusarium - and the near-by use of genetically modified (GM) soybean cultivars. An economic evaluation based on three years of research at the Neely-Kinyon Long-Term Agroecological Research site near Greenfield, IA revealed that food-grade organic soybean could return $1160 to 1250 ha(-1) compared to $235 for conventional soybean grown in a 2-yr rotation with corn (Zea mays L.). Weed control challenges are site-specific, being closely associated with the weed seed bank populations and crop management strategies used prior to converting to organic crop production. The amount of stained soybean seed is variable generally increasing from NE to SW Iowa because of warmer winter temperatures. At the Neely-Kinyon site, staining ranged from 12 to 22% and 7.5 to 10% while yields averaged 2.4 to 2.8 and 3.5 to 3.8 Mg ha(-1), in 2001 and 2002, respectively. Stained soybean seed is currently rejected for food-grade markets (e.g. tofu), but increasing demand for organic meat and a small premium for organic feed-grade soybean has encouraged producers to continue growing the crop. The primary concern that organic producers have regarding GM crops is the increased risk of their crop failing a GM test when sold because of pollen drift or other contamination sources. Despite the many challenges, increasing consumer demand for certified organic soybean certainly warrants more aggressive and participatory research around the world.