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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #385120
Research Project: Agroecosystem Benefits from the Development and Application of New Management Technologies in Agricultural Watersheds

Location: Agroecosystems Management Research

Title: Multispecies cover crops in organic agricultural systems in the upper U.S. Midwest

Author
item Logsdon, Sally
item CAMBARDELLA, CYNTHIA - Retired ARS Employee
item O'Brien, Peter

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2021
Publication Date: 11/10/2021
Citation: Logsdon, S.D., Cambardella, C.A., O'Brien, P.L. 2021. Multispecies cover crops in organic agricultural systems in the upper U.S. Midwest. Agrosystems, Geosciences & Environment. 4(4). Article e20221. https://doi.org/10.1002/agg2.20221.
DOI: https://doi.org/10.1002/agg2.20221

Interpretive Summary: Cover crops are non-harvested crops that are planted into or after the main crop, which are intended to protect the soil from erosion after the main crop season into the next spring. Over time, the cover crops may improve the soil itself, and hence the crops. In this study USDA-ARS researchers in Ames, Iowa examined cover crops planted into or after main crops of corn, soybean, and oat. This study showed that cover crops grew best after oat since there was a longer season and cover crop growth was not outcompeted by corn or soybean main crop. One of the cover crop mixes contained some plants that could survive the winter; however, turnips and hairy vetch often did not survive well in the upper Midwest winters, but rye and sometimes red clover better survived the winter. The cover crops had no effect on the main crop yields during this three-year study, so a longer study would be useful. This information is important for scientists and crop advisors on the best use of cover crops in the upper Midwest.

Technical Abstract: Establishing cover crops (CCs) in organic systems for the upper Midwest can be a challenge due to shorter growing seasons. The aim of this systems study was to compare CC management implemented in a tilled organic system. The main crops were oat (Avena sativa L.), corn (Zea mays L.), and soybean (Glycine max (L.) Merr.). Winter-hardy (WH), or winter-kill (WK) cover crop mixes were planted after oat, and red clover (Trifolium pratense L.) was planted into oat for the control (C) treatment. The CC were planted into corn (WH, WK) or after corn harvest (rye - Secale cereale L., C). Turnips (Brassica rapa L. ssp rapa) were planted after or into soybean. Main crop yields were not affected, but CC performed poorly in corn and soybean for both fall and spring due to dense main crop canopy, dry surface soil, late harvest and cold fall temperatures. The CC biomass production was greatest following oat because of the longer growing season but still did not establish well as the red clover C needed to be replanted both in 2018 and 2019. Photographic analyses to calculate leaf area index, ground cover, and evapotranspiration revealed few treatment differences throughout the study, which were more likely caused by weather conditions rather than differences in the WH, WK, and C management practices. These findings further demonstrate the difficulties of consistently establishing CC in corn-soybean rotations for the upper Midwest and highlight the need for developing new strategies.