Evaluation of Soybean Varieties for Certified Organic Production 2004

Materials and Methods Varieties selected for the 2004 organic soybean variety trial included the following: 6024FG (from Gold Country Seeds), IA2064, IA3017, MRK0327, MRK0330, MRK 0431, NC+2A83, NC+3A44, Pioneer 9305, Schillinger 240F.Y, Schillinger 254F.P, and Schillinger 284F.HP.Y. Plots measuring 20 × 100 feet were laid out in a completely randomized block design with four replications of each variety. Soybeans were planted at a depth of 2 inches on June 7, 2004, at a rate of 200,000 seeds/acre. Weed control was established through the following procedures: rotary hoeing on June 16, 28, and July 8; cultivation on June 30, July 13, and July 28, and walking plots on June 30 and July 20. Plant stands were counted on June 22, 2004. Bean leaf beetle sampling occurred on September 9, by sweeping across plants in each plot with a 15-in. diameter sweep net. Insects were placed in Zip-lock bags and transported in coolers to Iowa State University. Insects were frozen until enumeration in the laboratory. Soybeans were harvested on October 12. The percentage of stained soybeans was determined by counting the number of stained soybeans in a 60-gram sample that was randomly collected from the harvest of each plot.