Survey: Cover Crops Boost Yield and Weed Control

Survey: Cover Crops Boost Yield and Weed Control

Following the use of cover crops, farmers reported increased yields of corn, soybeans, and wheat, and improvement in the control of herbicide-resistant weeds, according to a nationwide survey. In addition, the survey of 2,012 farmers showed acreage planted in cover crops has nearly doubled over the past five years.

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Survey participants — 88% of whom use cover crops — reported that after cover crops:

  • Corn yields increased an average of 2.3 bushels per acre, or 1.3%;
  • Soybean yields increased 2.1 bushels per acre, or 3.8%; and
  • Wheat yields increased 1.9 bushels per acre, or 2.8%.

This marks the fifth consecutive year in which the survey reported yield increases in corn and soybeans following cover crops. It is the first year the survey team was able to calculate the impact of cover crops on wheat yields. The poll was conducted by the Conservation Technology Information Center (CTIC) with help from Purdue University and funding support from USDA’s Sustainable Agriculture Research and Education (SARE) program and the American Seed Trade Association (ASTA).

“In addition to yield increases, farmers reported other benefits to cover crops, ranging from improved soil health to better control of herbicide-resistant weeds,” notes Rob Myers, regional director of Extension programs for North Central SARE at the University of Missouri. “For instance, 85 percent of the farmers who used cover crops said they have seen improvements in soil health. That reflects long-term thinking and a growing understanding of the enduring value that cover crops deliver.”

Myers adds that 69% of the respondents said cover crops always or sometimes improved control of herbicide-resistant weeds. That is a significant number, he notes, as a majority of respondents (59%) reported having herbicide-resistant weeds in at least some of their fields.

Since SARE and CTIC began their annual cover crop survey in 2012, there has been a steady increase in cover crop acreage among participants. In this year’s survey, farmers said they committed an average of 400 acres each to cover crops in 2016, up from 217 acres per farm in 2012. They expected to increase their cover crop planting in 2017 to an average of 451 acres.

The timing of cover crop planting is also evolving. Cover crops are typically planted in the off-season from cash crops, providing ground cover, nutrient sequestration and scavenging, weed suppression, and soil health improvements. Approximately three out of four cover crop acres in the survey were planted after harvesting a cash crop, but the practice of inter-seeding covers into growing cash crops is an emerging trend — 27% of the respondents said they seeded cover crops at sidedress fertilization time or in late summer.

At the other end of the cycle, “planting green” — seeding cash crops directly into living, green cover crops, then terminating the covers — had been tried or used by 39% of the respondents. They said the approach helped suppress weeds, manage soil moisture, and maximize other benefits of cover crops. Planting green was uncommon just a few years ago.

The last USDA Census of Agriculture found that farmers planted more than 10 million acres of cover crops in 2012. The new agricultural census, which will begin this fall, is likely to find several million additional acres of cover crops planted in 2017.