Soybean seeded [ Glycine max (L.) Merr.] early into standing wheat ( Triticum aestivum L.) using relay intercropping (RI) and seed-coat technology may reduce mechanical damage and soybean interference to wheat. Field research at Novelty from 2003 to 2005 and Albany in 2004 evaluated effects of seed coat technology on wheat and soybean response, and gross profits of RI soybean using seed coat technology compared with selected full season (FS) wheat or soybean and double crop (DC) wheat-soybean. Wheat grain yield in the absence of soybean was 10 bu/acre greater in narrow (7.5-inch) than wide (15-inch) rows. Relay intercropped Intellicoat (ITC) treated 5143 soybean delayed germination and increased 15-inch wheat grain yields 8 bu/acre compared to non-coated (NC) 5143. At Novelty, RI 5143 ITC yield was similar in all three years and 7 bu/acre greater at Albany than 5143 NC. In 2005, dry conditions in mid- to late June reduced RI stands and yields compared to DC soybean at Novelty. Double-cropped 5143 NC soybean had greater gross profits than RI 5143 ITC when wheat and soybean prices were high. However, RI 5143 ITC gross profits were greater when soybean prices were high and wheat prices were low. The RI system using ITC maintained soybean yields and did not reduce wheat yields due to mechanical damage or soybean interference compared to non-coated or fungicide-only coating.
