Study Shows a Single Cover Crop can Outperform Mixtures

Aug 30, 2022

Cover crops can be a valuable tool for weed suppression—successfully competing with weeds for light, water, nutrients and space. As a result, new cover crop seed mixes are growing in popularity as a sustainable option for weed management. But do these diverse mixtures do a better job at suppressing weeds than a single, monoculture cover crop?

In this multiyear field study featured in the journal Weed Science, a team from Agriculture and Agri-Food Canada set out to answer that question. They compared 19 monoculture cover crops from four taxonomic groups (brassica, forb, grass, and legume), with 19 mixtures containing multiple plants that represented from one to three cover crop species.

Their results demonstrated that weed biomass dramatically declined as cover crop biomass and diversity increased. However, monocultures of buckwheat, oat, pearl millet or sorghum sudangrass were typically more productive and more weed suppressive than the average mixture. This result was consistent across regions, seasons, mixture composition and functional diversity.

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Video: Dicamba Returns for Georgia Farmers: What the New EPA Ruling Means for Cotton Growers

After being unavailable in 2024 due to registration issues, dicamba products are returning for Georgia farmers this growing season — but under strict new conditions.

In this report from Tifton, Extension Weed Specialist Stanley Culpepper explains the updated EPA ruling, including new application limits, mandatory training requirements, and the need for a restricted use pesticide license. Among the key changes: a cap of two ½-pound applications per year and the required use of an approved volatility reduction agent with every application.

For Georgia cotton producers, the ruling is significant. According to Taylor Sills with the Georgia Cotton Commission, the vast majority of cotton planted in the state carries the dicamba-tolerant trait — meaning farmers had been paying for technology they couldn’t use.

While environmental groups have expressed concerns over spray drift, Georgia growers have reduced off-target pesticide movement by more than 91% over the past decade. Still, this two-year registration period will come with increased scrutiny, making stewardship and compliance more important than ever.