P-695 - Benefits of relay cropping soybeans with winter cereals in Iowa

Relay cropping (RC) is an innovative agricultural practice that can have multiples benefits such as increased land use efficiency, being a valuable management tool for controlling weed and pest, and improved soil and water quality, but also has the potential to enhance overall crop productivity in comparison with conventional crop monocultures (MC). We evaluated weed and pest infestation, grain yields and inputs to income of soybeans relayed with winter small grains at two sites in Iowa (ISU Agricultural Engineering and Agronomy Farm (AEA), Boone, Iowa and Big Boulder Farms (BBF), Monticello, Iowa). Winter crops were planted in the fall 2023, soybeans were interseeded into a living winter crop in mid-May 2024, mature winter crops were harvest in July, and soybeans plots were harvested in September/October depending on the location. The weed infestation (18 weed species) in winter barley-soybean RC and cereal rye-soybean RC was significantly lower (P < 0.05) compared with no-till fallow/soybean MC at AEA, and no major weed infestations were observed at BBF across eight replications. No major diseases of soybean were observed in soybean RC with cereals, compared with MC soybean. Soybean yields in the RC plots were generally slightly higher than those of MC soybeans. At AEA, the yield of soybean RC/winter barley was 37.36 bu/ac, soybean RC with winter rye yielded 36.49 bu/ac, vs MC soybean with 34.27 bu/ac for 1.4 maturity group. At BBF, soybean yields were 70 bu/ac in soybean RC with cereal rye compared with 67 bu/ac in MC soybeans for the 3.0 maturity group.