Watching an airplane that traditionally is used to spray row crops during the summer, more than 50 people watched a demonstration of aerial seeding of winter rye in a cornfield near Webster City, Iowa, that was yet to be harvested.
"Cover crops basically turn the whole field into a buffer strip," says Bruce Voigts, president of the Mississippi River Basin Initiative. Holding a milk carton with sprouting winter rye, he described the government funds available, as well as the benefits of planting a cover crop just ahead of harvest time, whether from the air or with a seed drill following the combine.
Voigts shared a study completed in 2005 by the U.S. Department of Agriculture — Ag Research Service that noted that small grain cover crops were effective at accumulating nitrates that would otherwise leach out of the soil profile and contaminate groundwater, wells, streams and lakes.
Researchers, who tested this study for 3 years in Iowa, determined that rye, over-seeded into no-till soybeans, reduced interrill erosion by 54% and rill erosion by 90%. Oats reduced interrill and rill erosion by 26% and 54%, respectively.
Interrill erosion is when raindrops strike exposed soil detaching the soil particles, splashing them into the air and into shallow overland flows. Rill erosion is the removal of soil by runoff from the land surface.
When the cover crops are killed in the spring ahead of planting, the captured nitrate is returned to the soil by plant residue.
"Small grain cover crops," the study adds, "can reduce the number of early season weeds and provide mulch for continued weed suppression."
Voigts and others recommend seeding cover crops in corn, just ahead of harvest, and in soybeans as leaves turn yellow. With the seed on the ground, the falling soybean leaves will protect them until germination.
Now in his second year of experimenting with cover crops, Arliss Nielsen of Woolstock says he is still learning how to use small grains to benefit his soil, but said the earlier the grains can be seeded, "the more sunlight they'll get to become established."
Where aerial applications will require about 90 pounds of seeds per acre, or about 1.3 million seeds, drilling small grains following the combine will be successful at a rate of 50 pounds per acre. But Nielsen believes that as busy as producers are with hundreds and even thousands of acres to harvest, most will likely opt for aerial seeding "just to get it done."
He says he is seeing a gradual increase in yields as he adopts more land management practices and moves away from conventional tillage.
"We're assuming these tests are beneficial," he says. "We're using several practices like no-till, cover crops, variable-rate fertilization and increased plant populations. We can't distinguish any one practice. They are all helping."
He says he started seeding small grains using Environmental Quality Incentive Program funds from the NRCS. He adds he wasn't sure how it would work out.
"But you never know what will happen until you try it," he says. "We're learning and we think we are heading in the right direction."