WASHINGTON, D.C., The Fertilizer Institute - A potentially record-setting U.S. corn harvest is underway. Many farmers can attribute the use of cover crops as one of multiple best management practices (BMPs) that help them increase yield year after year. Combined with BMPs of The Fertilizer Institute's 4R Nutrient Stewardship program that promotes the application of nutrients at the right source, right rate, right time and right place, farmers further ensure top production.
"Interest in cover crops has grown immensely the past few years," said Eileen Kladivko, an agronomist and cover crops specialist with Purdue University. "Cover crops are an integral part of modern, sustainable agriculture. With improved plant genetics, synthetic fertilizers, pesticides and machinery helping to increase yields, but sometimes masking soil degradation, cover crops become an important part in helping to improve underlying soil resources and in obtaining the full potential benefits from additional crop inputs."
She adds that different cover crops provide different benefits and growers must decide what their primary objectives are when selecting cover crops.
"Cover crops are often planted for their benefit to the soil or environmental quality and not for harvest," Kladivko added. "Some may be suitable for grazing or haying, but this means they should be managed as forage crops."
In general, she says the benefits of cover crops fall into these categories.
• Scavenge or, "trap" nitrogen and protect water quality - the crops trap residual soil nitrate to prevent it from leaching into groundwater.
• Produce nitrogen - legumes fix atmospheric nitrogen for their own use. Once terminated, much of the nitrogen is released to succeeding crops as residues decompose.
• Prevent erosion - the crops cover the soil surface to protect against water and wind erosion.
• Build soil quality and/or recycle nutrients - cover crops improve soil's physical properties, increase soil's organic matter and increase soil's biological activity.
• Suppress weeds - some crops can suppress weeds by competition, shading or allelopathy.
• Enhance wildlife habitat - cover crops can provide water, cover and food for wildlife and increase landscape diversity.
These benefits will vary from year to year, depending on weather and the amount of growth of the cover crop, she advises.
"After a drought year, it's even more important to plant a cover crop in the fall," Kladivko adds. Once the rains return, the cover crop will be there to scavenge some of those nutrients not used by the cash crop."
Cover crops make winners
Kladivko's and her peers' messages about cover crops aren't falling on deaf ears. In fact, practicing those recommendations helped farmers across the country be honored as 4R Advocates for the 4R Nutrient Stewardship Program.
George Brand is a 4R Advocate and one of the owners of Brand Dairy Farms in Waterloo, Indiana. The multi-generational business also includes 2,500 acres of row crops that include corn, soybeans, wheat and hay.
All of Brand's farmland is in the St. Joseph watershed, which drains into the Maumee River and Lake Erie. Thus, protecting water quality is very important to them. Grass waterways, complemented with filter strips along open ditches and wascobs help control soil runoff and erosion.
"We started incorporating cover crops in our operation a few seasons ago," Brand said. "We included rye, crimson clover and radishes. It worked so well, we can't wait to put them on more acres."
Chris VonHolten, a 4R Advocate who farms 1,080 acres of corn and soybeans near Walnut, Illinois, couldn't agree more with Brand.
"I'm always evaluating new products, technology and improved practices," he said. "I adopt those that improve the efficiency of my farm. If you're not trying to learn something, you'll get in a rut."
VonHolten used conservation tillage from the start and all acres are now no-till or strip-till. Waterways that help control erosion make up 16 acres of the property.
Controlling this potential runoff helps keep nutrients in place. Cover crops help keep nutrients where they belong, too. In 2013, he tested a cover crop mix on two locations to help absorb excess nutrients and prevent soil erosion.
"I chose radishes and oats because they winterkill, so a spring burn down doesn't need to be applied, which further protects the environment," he said.
Whether it's planting, applying pesticide, applying or retaining nutrients, all practices are mapped and monitored to ensure correct application amounts for each product.
"Each of these practices has its role, but combined, they all work together for the benefit of the farm, the environment and the community," VonHolten added. "We're going to keep using cover crops and may even experiment with a summer companion crop."
The winterkill VonHolten mentions is important. Growers should plan in advance how they will control and terminate cover crops.
"Some cover crops do not overwinter, so farmers generally don't need to plan for termination in the spring," Kladivko says. "Oats and oilseed radish are two common examples. On other crops, herbicide applied according to label directions, tillage, mowing or roller-crimping are effective termination methods."
Helps the land
John Scates with Scates and Sons Farm in Shawneetown, Illinois, is conscientious about the environment where he farms. He also makes every attempt to keep a proper balance on nutrients on the multiple soil types in his 17,000-acre corn, sorghum and wheat operation.
He's an advocate of cover crops, too. He uses a combination of grasses and legume to sequester nutrients in the root zone during the winter fallow periods.
"The soil is our most important asset," Scates says. "Doing the right thing related to nutrients pays off economically and environmentally."
John Werries and his son, Dean, operate Werries Farm, LLC, in Chapin, Illinois. He says his only regret about cover crops is that he didn't use them sooner.
"The first year we tried them, we sowed a small amount of cereal rye," Werries said. "We've added more of it since. Plus, we're enthused about cover crops. They stop soil erosion. They sequester nutrients and reduce compaction. When they die, they add organic matter. When we had excessive rain, our cover crops were in good shape and kept our soil from washing away."
Like Scates, Werries agrees soil is the most important asset.
"We've got to take care of our soil," he said. "Cover crops help save it. Cover crops can be used on a large scale and I encourage farmers to get with it. Most of us have the equipment and management ability to do this. On top of that, there are those out there who've done this longer than most of us. They're willing to share their knowledge."
Kladivko concurs. She recommends checking with Extension agents, crop advisers and the Midwest Cover Crops Council at http://www.mccc.msu.edu. More information about cover crops and the 4R Nutrient Stewardship program is available at www.nutrientstewardship.org.
"Good stewardship practices that include cover crops will help ensure we continue to achieve excellent yields over the long term," she added.
Those practices will undoubtedly help make a few more "winners," too.