Farmers across the country reported higher yields from use of cover crops in 2012, especially in drought zones, according to a study carried out by the Conservation Technology Information Center. More than 700 farmers responding to the survey reported yield increases for corn and beans following the use of cover crops.
The survey of experienced cover-crop farmers took place last winter. Responding farmers had more than 200,000 acres under cover crops, about 10 percent of the national cover crop acreage.
Farmers reported that dormant-season cover crops led to increased yields of 9.6 percent for corn and 11.6 percent for soybeans over fields without cover crops. In regions with severe drought, yield differences were even higher: 11 percent for corn and 14.3 percent for beans. Farmers spent, on average, $40 per acre establishing their cover crops.
"The yield improvements provided from cover crops in 2012 were likely a combination of factors, such as better rooting of the cash crop along with the residue blanket provided by the cover crop reducing soil moisture loss,” says Dr. Rob Myers, a University of Missouri agronomist. "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 impact 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 percent 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's Sustainable Agriculture Research and Education Program.
Cover crops can be used in gardens of all sizes. Consider adding one of these five cover crops to your small-scale garden.