Higher Yields (and more) with Cover Crops

Farmers across the country reported higher yields from use of cover crops, especially in drought zones, in 2012. Over 700 farmers responding to a survey reported yield increases for corn and beans following cover crops.

The Conservation Technology Information Center carried out a survey of experienced cover crop farmers last winter. Responding farmers had over 200,000 acres under cover crops, about 10% of the national cover crop acreage.

Farmers reported that dormant-season cover crops led to increased yields of 9.6% for corn and 11.6% for soybeans over fields without cover crops. In severe drought regions, yield differences were even higher: 11.0% for corn and 14.3% for beans. Farmers spent, on average, $40/acre establishing their cover crops.

“The yield improvements provided from cover crops in 2012 were likely a combination of factors,” stated Dr. Rob Myers, a University of Missouri agronomist, “such as better rooting of the cash crop along with the residue blanket provided by the cover crop reducing soil moisture loss. Also, where cover crops have been used for several years, we know that organic matter typically increases, which improves rainfall infiltration and soil water holding capacity.”

Cover crops in a crop rotation can provide a range of benefits to soils, crops, and water quality. They can control erosion, smother weeds, reduce soil moisture loss, and add nitrogen and organic matter to the soil. Nearly all survey respondents identified “soil health” as a key benefit of using cover crops.

Another benefit, cover crops can also slow climate change or reduce its impacts on crops. Cover crops increase capture of carbon from the air when they are used during the cash-crop dormant season. They add more carbon to the soil, where it can be stored, than cash crops alone. Mixtures of legumes and grains as cover crops can reduce synthetic fertilizer used for cash crops, cutting emissions of potent greenhouse gases.

Acreage of cover crops has increased nearly 40% per year since 2009, and knowledge of how to manage them has grown. USDA’s handbook Managing Cover Crops Profitably is a good guide to crops, seed sources, planting techniques, and more. Both the handbook and the full survey report are available free online from USDA SARE.