Corn Yield Is Not Reduced by Mid-Season Establishment of Cover Crops in Northern Great Plains Environments
2014
Bich, Alex D. | Reese, Cheryl L. | Kennedy, Ann C. | Clay, David E. | Clay, Sharon A.
In northern climates, establishment of fall cover crops after corn or soybean harvest is difficult due to cold and dry conditions. This study examined an alternative option: in-season cover crop seeding, timed for plants to emerge just following the critical weed-free period of corn (Zea mays L.) to allow establishment and growth without compromising yield. Crimson clover (Trifolium incarnatum L.), lentil (Lens culinaris Medik.), and winter wheat (Triticum aestivum L.) seed was blended and either drill (DRL) or broadcast (BRD) seeded into corn at the five-leaf (V5; late June) growth stage at three South Dakota sites (7 site years) and at V3 at one site in 2 years. Visual observations in mid-July verified establishment, and aboveground live (e.g., green) biomass was quantified at about R4 (soft dough), prior to corn grain harvest. Cover crop establishment and growth were superior with DRL seeding, which had rapid establishment and more aboveground biomass compared with BRD seeding. Although the total biomass in the V3 and V5 DRL treatments was similar, corn yield was reduced 10% in the V3 seeded plots but was unaffected by V5 seeding. Soil microbial communities were similar to the no-cover-crop control. Our results suggest that cover crops can be established successfully in standing corn at the V5 growth stage without compromising grain yield.
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