Overseeding cover crops on corn and soybean response in upstate Missouri

Abstract

AbstractField trials were conducted near Novelty, Missouri from the spring of 2016 to the fall of 2018. Main crops, corn (Zea mays) or soybean [Glycine max (L.) Merr], were planted and rotated to the other crop the following year. Cover crop (CC) treatments were overseeded into the main crop at V5, V10, and VT in separate corn experiments and at R6 in soybean to determine the effect of overseeding CCs on main crop yield, CC biomass, weed biomass, and rotational crop yield. No yield differences were detected in corn or the subsequent soybean crop when corn was overseeded at V5 with a CC. Neither CC nor weed biomass was greater than the non‐treated control (NTC). Year by treatment interactions were present for CC biomass and subsequent soybean yield when corn was overseeded at V10. In 2017, CC biomass was 348 to 820 lb ac−1 greater than the NTC, but soybean yield was similar to the NTC in both years. Biomass of CCs overseeded into soybean at R6 was 2240 to 2950 lb ac−1 greater in 2017 than in 2018, and some CCs reduced weed biomass in 2017. Some cover crops reduced corn yield 29 to 57 bu ac−1 following overseeded soybean. Excluding wheat, CC treatments did not reduce main crop yield in 2018. Lesser CC biomass may reduce yield loss of rotational crop suggesting earlier springtime termination of CCs might prevent excessive biomass accumulation.