According to an increasing number of Iowa farmers, agronomists and soil conservationists, cover crops such as rye, wheat and clover are environmentally beneficial, and with proper management won’t inhibit yields in various crop systems, including no-till and organic farming.
At a recent cover crops workshop, dozens gathered to discuss and learn more about the many benefits and varieties of cover crops and ways to successfully plant and manage them.
Research by the USDA’s Agricultural Research Service National Laboratory for Agriculture and the Environment, or NLAE, at Ames shows cover crops planted in the fall between harvest and planting of spring crops help reduce soil erosion, limit nitrogen leaching, suppress weeds, increase soil organic matter and improve overall soil quality.
Small-grain cover crops increase surface cover, anchor corn and soybean residues, and increase water infiltration. Several cover crops, like turnips and radishes, are also suitable for grazing by livestock and wildlife. Aerial seeding of cover crops in August or after harvest is also an option.
• Farmer experiences show cover crops work in various crop production systems.
• Researchers have developed new management strategies for cover crops.
• Covers can be used in organic systems with light tillage, or no-till systems, too.
Success in organic
One of the panel members at a recent workshop, farmer Earl Hafner of Panora, says a mix of cover crops serves a vital purpose for his organic row-crop and livestock operation. On his central Iowa farm, he plants winter-hardy grains (cereal rye), winter-hardy legumes (red clover and hairy vetch) and forage covers (radishes). Hafner says many different types of root systems improve soil quality and its holding capacity. “A mix of cover crops allows water-soluble nutrients to be captured and available for the next year’s crop,” he notes.
Hafner grows corn, soybeans, hay and small grains on about 1,500 acres and runs a 250-head cow-calf herd on another 500 acres. He practices tillage, but only the top 4 inches of soil. He says cover crops help keep fall-applied manure from washing away. “When you turn cover crops over that are 6, 8 or 10 inches tall, it helps keep the phosphorus on the farm, reducing leaching,” he says. “As an organic farmer, I need those nutrients.” Because Hafner practices some tillage, his soils have less crop residue cover to benefit earthworms. “Cover crops help develop soil structure. They serve as the biology that earthworms can feed on,” he adds.
Success in no-till
Cover crops have been an important part of Steve Berger’s no-till farming operation in Washington County for more than 10 years. Berger grows corn and soybeans on about 2,500 acres in southeastern Iowa, where he has no-tilled for more than 30 years.
Berger says a rye cover crop combined with no-till helps control erosion, promotes root growth and even improves row-crop production. “Over the long term, the organic matter buildup has helped increase my yields,” he says.
He plants cereal rye as soon as possible after harvest at a rate of 50 pounds per acre, and knifes in hog manure or spreads turkey manure before the winter freeze. He sprays the rye in early April, before planting corn. Berger allows rye to grow for a longer period before planting soybeans.
Rye typically grows to 4 to 6 inches before Berger plants corn, and 8 to 10 inches before he plants soybeans. He says timing of manure application is key to producing high-yielding cash crops.
“I hear farmers say you can’t produce high-yielding corn while integrating cover crops, but I disagree,” he says. “Cover crops build soil quality, and if you fertilize in a timely way, it can increase yields.”
Jeremy Singer, a research agronomist with NLAE at Ames, promotes winter-hardy cereal cover crops such as rye, winter wheat and triticale (cereal rye and winter wheat cross) because they are easy to establish, are relatively inexpensive, and provide erosion control in the fall and spring. Singer agrees with Berger that, over the long term, cover crops will not hurt cash crop yields. “I feel pretty confident that if you follow our current recommendations, you won’t see yield reduction in corn or soybeans from planting cover crops,” he says. “In fact, cover crops can suppress weed emergence and growth,” and this suppression helps protect yields.
Cover crop financial assistance
USDA’s Natural Resources Conservation Service is offering three years of financial assistance to eligible producers through the Environmental Quality Incentives Program to help offset the cost of introducing cover crops.
To plant winter-hardy species, such as cereal rye and winter wheat, NRCS will pay $60.03 per acre per year; for planting non-winter-hardy species, such as oats and spring wheat, NRCS will pay $41.25 per acre per year; and for living mulch, $56.18 per acre per year.
Limited-resource producers, beginning farmers, tribal farmers and socially disadvantaged producers are eligible for a higher payment rate. For example, these farmers would receive $108.19 per acre per year through EQIP to introduce winter-hardy cereals to their operation.
Get more information
For more information about establishing, managing and overall benefits of cover crops, visit your local NRCS office. Also, a helpful new publication “Cover Crops: A guide for Iowa Producers” is online at www.ia.nrcs.usda.gov/news/brochures/
Johnson is a public affairs specialist for NRCS in Iowa.
BEANS WILL GROW: This late-June picture shows soybeans growing in cereal rye cover crop, which was sprayed with herbicide a few months earlier.
Photo courtesy of Laura Greiner, NRCS