Interseeding cover crops in corn
2020
Brooker, Aaron P. | Renner, Karen A. | Sprague, Christy L.
Farmers benefit from ecosystem services that cover crops provide, but time constraints limit the opportunity to seed cover crops following corn (Zea mays L.) harvest in the upper Midwest. Interseeding cover crops in corn during the early vegetative growth stages lengthens the cover crop growing season; however, cover crops may have difficulty establishing in standing corn, or conversely, compete with corn and reduce yield. The objectives of this research were to determine cover crop establishment when broadcast interseeded in corn from the V2–V7 growth stages, suppression of weeds by cover crops, and effects of cover crops on corn grain yield. Annual ryegrass (Lolium multiflorum Lam.), crimson clover (Trifolium incarnatum L.), oilseed radish (Raphanus sativus L.), and a three‐species mixture were interseeded in four site‐years in Michigan. Annual ryegrass density was highest compared with oilseed radish and crimson clover 30 d after interseeding and at harvest in October. Cover crop density was highest at the V4–V7 interseeding timings. Annual ryegrass produced more fall biomass (186 kg ha⁻¹) compared with crimson clover (112 kg ha⁻¹), and fall biomass was greatest at the V2, V3, and V5 interseeding timings. Spring biomass was 384 and 180 kg ha⁻¹ for annual ryegrass and the cover crop mixture, respectively; these treatments reduced winter annual weed biomass. Corn grain yield was unaffected by cover crops at any interseeding timing. Crimson clover did not establish well in this experiment. Annual ryegrass and oilseed radish interseeded in V2–V7 corn did not reduce corn grain yield.
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