With typically wet springs and dry summers, Gail Fuller at Emporia, Kan., needs to manage moisture on his farm ground so it's available to crops at the right time.
Because the past 10 years have been anything but "typical," Fuller has found that cover crops are his best moisture management tool.
"Our average local rainfall is 32 inches, but the past few years we've had less than 20 inches of rain for the year. However, in 2009, we had more than 50 inches of rain," Fuller said. "We do a lot of guessing and it's easy to guess wrong."
It's taken Fuller a number of years to learn about the benefits of cover crops and find the specific mixes that work best on his farm north of Emporia. Numerous types of soils that include silty loam, clay loam and some bottom ground are found on Fuller's acres. In the past, erosion was a serious concern. Efforts to reduce erosion led Fuller to experiment with cover crops. He has since discovered that the practice of planting cover crop cocktails offers numerous benefits.
"When you plant a cash crop such as wheat or corn, that crop is only actively consuming water for a few months of the year," Fuller said. "In the months when the soil is bare, the soil profile can only hold a certain amount of water. A cover crop can help absorb excess moisture, reducing soil erosion. It also conserves the moisture in the soil profile and actually traps more moisture for the soil profile than if the soil was bare. The cover crop builds organic matter and provides residue, so there are a lot of good reasons to use cover crops."
In his first cover crop experiment, Fuller was focused on saving a 25-acre field that had been used for grazing. He describes erosion issues there as "horrible" and notes that it took three years with use of a cover crop to stabilize the field.
"That was my first success with cover crops," Fuller said. "For several years I used a forage oats and forage peas mix that I harvested, chopping it for haylage to use in our feedlot. Even when I harvested that cover crop, I had the best corn crop ever when I planted it after the forage oats and forage peas mix. Now I plant cover crops and leave them on the field so I get the benefit of all the nutrients and organic matter that they provide. The more organic matter the soil has, the more water holding capacity it has."
Fuller notes that there is no "recipe" for a successful cover crop that can be planted with cash crops. His own search for a corn crop companion began when a stand of alfalfa didn't emerge satisfactorily. It was mid-July before he decided to plant sunflowers in the field and let the alfalfa go.
"We sprayed the alfalfa with Roundup, but didn't get a good kill," Fuller said. "It rained shortly after we planted sunflowers into the field. Both the sunflowers and alfalfa came on. Even though alfalfa is such an aggressive crop in terms of nutrient use, we had the best sunflowers from that field that we had ever harvested. That experience caused me to explore use of subterranean clover as a companion plant for corn. I worked with Jill Clapperton (soil scientist) and Gabe Brown (North Dakota farmer) and now use clovers with my corn crops."
Fuller explains that monocultures are not found in natural settings. Soil scientists are starting to discover that compatible companion plants work together in symbiotic relationships to improve plant health and productivity.
"We're using between five and eight different crops in our wheat fields every year," Fuller said. "To find the right plants and mixes for your field, you have to first decide which issue you want to address first. Is it erosion, organic matter or moisture management? The answer to that question will help define which cover crops will help achieve the desired results."
Fuller recommends conference presentations, Internet research and personal trial and error as resources to help identify cover crops in a specific field.
"There is a lot to learn about how cover crops work," he said. "Even planting the same mix a couple of weeks apart can result in very different results. Decide what you need to accomplish and start searching and experimenting. Cover crops will always be part of my farming strategy now."