Yield and nitrogen recovery from field-grown supernodulating soybean.

摘要

Experiments were conducted to determine the yield and growth characteristics of a soyabean genotype with supernodulation, and to determine the influence of supernodulation on the yield and growth characteristics of winter wheat grown after soyabeans. Field studies were conducted in 1993-95 under rainfed conditions at Arlington, Wisconsin, on a Plano silt loam (fine-silty, mixed, mesic Typic Argiudoll) and under irrigated conditions at Hancock, Wisconsin on a Plainfield sandy loam (loamy-sand, mixed, mesic Typic Udipsamment). Four soyabean genotypes were evaluated at R3, R7 and R8 growth stages included supernodulating, the normal nodulating parent of the supernodulating line, a non-nodulating line, and the normal nodulating parent of the non-nodulating line. The non-nodulating line provided a baseline of soyabean performance without N2 fixation capabilities. Winter wheat cv. Merrimac sown after soyabean harvest was evaluated at Z37, Z50, and Z90 growth stages. Depending on location, the supernodulating genotype increased soyabean nodule density by 43-135%, soil nitrate N at R3 growth stage by 34-48% and biomass N by 10-19% compared with the normal nodulating genotypes. However, at the R7 and R8 growth stages, soil nitrate N, plant biomass N andforage and seed yields were not different between the normal and supernodulating genotypes. Winter wheat grown after supernodulating soyabeans had no difference in soil nitrate N, biomass N, or forage or grain yield compared with normal nodulating genotypes. Based on these results, there does not appear to be any agronomic benefit to using supernodulating soyabeans compared with normal nodulating lines.