Newell R. Kitchen, a soil scientist for the U.S. Department of Agriculture Agricultural Research Service located on the campus of University of Missouri, has been researching the long-term impact of cover crops for more than 20 years. These measurements include soil and water quality tests.
“We are seeing a tremendous reduction in sediment, erosion and runoff from the fields we’ve been conducting research in,” Kitchen said.
One of the first things Kitchen found on claypan soils is that you would still have significant erosion with no-till practices in a typical soybean and corn rotation. However, with the addition of cover crops with the no-till practices, erosion is much more successfully controlled.
According to Drexel Atkisson, District Conservationist for the USDA, Natural Resource Conservation Service in Dade and Cedar counties, the cover crop is just one piece of the puzzle to regenerating our soil’s health. The entire picture of soil health is what we need to focus on.
“Cover crops are for the most part used on annually-planted crop land,” Atkisson said. “Cover crops do not work well in pastures; we need to take a different approach to improving soil quality in our permanent grass pastures. Cover crops fill in the gaps in between the normal crop rotation.”
Our soil is alive with millions of microorganisms (bacteria and fungi) that depend on a living root for their food source. When there is no root life, the microorganisms starve down and go into survival mode. “Cover crops provide these living roots year-round,” Atkisson said. “We want to prevent the dead time in the soil.”
Atkisson advises that to achieve long-term sustainability we need the following three things in place.
1. No tillage
2. A living root for 365 days
3. Rotation of four crop types (warm-season grass, cool-season grass, warm broadleaf and cool broadleaf)
“I really push no-till, we aren’t going to see this puzzle come together until you include no-till,” Atkisson said. “The cover crops will help, but without no-till we won’t get the impact we need.” Any type of tillage breaks up the soil structure at the surface and destroys pore space.
Corn, beans and wheat are the typical rotational crops in this area. So with these, Atkisson suggests to include a cool-season broadleaf.
“We want to provide mulch, which becomes a weed barrier, reduces our dependency on chemicals, and increases the soil organic matter,” Atkisson said. “The organic matter is the life blood of the soil. Organic matter comes from carbon which the cover crops help provide. This organic matter not only provides nutrients to the crops which lessen our dependency on commercial fertilizer but also helps negotiate wet and dry times by improving the soils water holding capacity.”
“This is the only way production agriculture is going to stay viable if we continue to see increases in the costs of inputs such as fertilizer, chemicals and fuel,” Atkisson said. “We have mined the native levels of organic manner from the soil over the last several decades, we are now starting to pay for that and will need to change our habits.”
