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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 #352517
Title: Crop density effect on interseeded cover crops, weeds, and grain yield

Author
item YOUNGERMAN, CONNOR - Cornell University
item DITOMMASO, ANTONIO - Cornell University
item CURRAN, WILLIAM - Pennsylvania State University
item Mirsky, Steven
item RYAN, MATTHEW - Cornell University

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/3/2018
Publication Date: 9/27/2018
Citation: Youngerman, C.Z., Ditommaso, A., Curran, W.S., Mirsky, S.B., Ryan, M.R. 2018. Crop density effect on interseeded cover crops, weeds, and grain yield. Agronomy Journal. 110:2478-2487.

Interpretive Summary: Cover crops provide a wide range of benefits to agricultural systems. However, farmers routinely struggle to get cover crops integrated into their crop rotation, as there is limited time after cash crop harvest for planting. New planter technology that permits interseeding cover crops into living cash crops, like corn and soybeans, provides a unique opportunity to increase cover crop adoption and performance. There is a need to fine tune this approach, therefore, we conducted a field experiment in New York, Pennsylvania, and Maryland to quantify how corn density influenced weed biomass, cover crop biomass, and corn grain yield. Increasing corn density negatively impacted interseeded cover crop biomass as well as indirect effects that were mediated by light transmission and weeds. At two sites, corn grain yield at the low corn density did not differ from corn grain yield at the standard density. Our results suggest that organic farmers may be able to: 1) improve weed suppression in corn by interseeding cover crops, and 2) optimize cropping system performance by planting corn at a slightly lower rate than what is typically used by organic growers. This research will be useful for organic researchers and farmers looking for strategies for optimizing cover crop establishment.

Technical Abstract: A field experiment was conducted at three sites (New York, Pennsylvania, and Maryland) in 2016 to test the effects of drill interseeding a cover crop mixture consisting of cereal rye (Secale cereal L.), annual ryegrass (Lolium multiflorum L.), hairy vetch (Vicia villosa Roth), and red clover (Trifolium pratense L.) into organically managed corn (Zea mays L.). We quantified the effects of corn density on weed biomass, cover crop biomass, and corn grain yield. Increasing corn density had a direct negative effect on interseeded cover crop biomass as well as indirect effects that were mediated by light transmission and weeds. At two sites, corn grain yield at the low corn density (3.71 plants m-2) did not differ from corn grain yield at the standard density (7.41 plants m-2). We also compared yield from plots with and without interseeded cover crops at the same standard corn planting density. Corn grain yield did not differ, but weed biomass at the October sample date was 31% lower in plots with interseeded cover crops compared to plots without. Our results suggest that organic farmers may be able to: 1) improve weed suppression in corn by interseeding cover crops, and 2) optimize cropping system performance by planting corn at a slightly lower rate than what is typically used by organic growers. Additional research should be conducted across a wider range of environments to determine corn planting rate recommendations that optimize corn yield, cover crop growth, weed suppression, and profitability in organic systems.