Relay Intercropping Soybeans into Wheat in Kansas

Abstract

Research was conducted to evaluate relay intercropping of soybeans [Glycine max (L.) Merr.] into winter wheat (Triticum aestivum L.) in areas of Kansas where length of growing season and inadequate rainfall limit the productivity of doublecropped soybeans. Objectives of the study were to: (i) examine the response of soybean and wheat cultivars to solid and skip-row planting patterns, and (ii) compare soybean and wheat performance when planted in monocropped and intercropped systems across a range of environments. Winter wheat cultivars Agripro ‘Mustang’ and Pioneer ‘2157’ were planted in 10-in. rows in a solid and one-out-of-three skip-row pattern at six environments in northern and western Kansas in 1985 and 1986. All but one environment was irrigated. Soybean cultivars ‘Sparks’, ‘Sherman’, and Asgrow ‘A3127’ were planted alone or intercropped into wheat at the late boot stage. Wheat yields in skip-row patterns were 13% lower than those in monocrop solid patterns, whereas intercropping soybeans into solid-seeded wheat reduced wheat yields 4%. Intercropped soybeans yielded 72% of monocropped soybeans. Soybean yields in the two intercropped planting patterns were similar, but there was a tendency for yields in the skip-row pattern to be greater than those in the solid planting pattern. No genotype X planting pattern interactions were observed for either crop. Relay intercropping did not appear to be a viable production option in far western kansas, where soybeans were less able to compete effectively with wheat. In eastern Kansas under dryland or irrigated conditions, or under irrigated conditions in the central part of the state, relay intercropping has the potential to increase gross returns over those of doublecropping or monocrop wheat production. Intercrop gross returns were only marginally higher than those for monocrop soybean production.