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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Publications at this Location » Publication #383341
Research Project: Enhancing Sustainability of Mid-Atlantic Agricultural Systems Using Agroecological Principles and Practices

Location: Sustainable Agricultural Systems Laboratory

Title: Evaluation of interseeding cover crop mixtures in mid-Atlantic double-crop soybean

Author
item PETERSON, CARA - University Of Maryland
item TULLY, KATHERINE - University Of Maryland
item VAN GESSEL, MARK - University Of Delaware
item DAVIS, BRIAN - North Carolina State University
item ACKROYD, VICTORIA - University Of Maryland
item Mirsky, Steven

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2021
Publication Date: 7/26/2021
Citation: Peterson, C.M., Tully, K.L., Van Gessel, M.J., Davis, B., Ackroyd, V.J., Mirsky, S.B. 2021. Evaluation of interseeding cover crop mixtures in mid-Atlantic double-crop soybean. Agronomy Journal. https://doi.org/10.1002/agj2.20824.
DOI: https://doi.org/10.1002/agj2.20824

Interpretive Summary: Grass cover crops are most typically grown in the mid-Atlantic region of the US because a short, late-planting window after cash crop harvest in the fall precludes establishment of legume cover crops. Legume cover crops, however, can provide key benefits such as N fixation that grass cover crops cannot. Interseeding cover crops into a standing cash crop could allow for successful legume establishment, though the practice requires the use of wide row spacing (30" or 76 cm). We conducted field trials to evaluate this no-till drill interseeding strategy and its effects on both cash crop growth and yield, and cover crop performance. Overall we found that a) soybean yield was not reduced when grown in wide rather than the more standard narrow rows and b) legume cover crop mixtures can be successfully interseeded into standing soybeans, so long as adequate light penetrates the canopy cover. This work will allow farmers to more readily integrate legume cover crops into their systems, potentially decreasing the amount of N that they must apply by increasing biological N fixation.

Technical Abstract: Winter legume cover crops can provide organic N to the subsequent corn (Zea mays L.) crop. However, legume cover crop adoption is limited in the mid-Atlantic US by the short establishment window after double-crop soybean (Glycine max (L.) Merr.) harvest. Interseeding legume cover crops into double-crop soybean with a modified seed drill could improve on previous interseeding methods. We conducted field trials in which mixtures of cereal rye (Secale cereale L.) + hairy vetch (Vicia villosa Roth), crimson clover (Trifolium incarnatum L.), red clover (Trifolium pratense L.), or winter pea (Pisum sativum var. arvense (L.) Poir) were interseeded into double-crop soybean on 76 cm wide row spacing. Overall, there was minimal to no effect of interseeding on double-crop soybean yield. Cover crop biomass varied by species, ranging from 1–7 Mg ha-1. Cover crop biomass N content was higher in cereal rye + legume treatments (mean 79 N kg ha-1) than in cereal rye alone (mean 30 N kg ha-1; p < 0.001). We also examined the effect of fall-interseeded cover crop mixtures on corn yield. Corn yields were low in 2018 due to heavy rainfall, yet we observed higher corn yields in the cereal rye + hairy vetch cover crop compared to no cover crop and cereal rye alone. In 2019, corn yields were higher, but there was no cover crop treatment response. This study demonstrated the specific benefits of integrating legumes into cropping rotations, namely increased N cycling efficiency and resiliency to extreme weather patterns characteristic of climate change.