Extension Communications
3614 Administrative Services Building
Ames, Iowa 50011-3614
(515) 294-9915
10/5/99
Contacts:
Greg Brenneman, Johnson County Extension, (319) 337-2145,
x1brenn@exnet.iastate.edu
Elaine Edwards, Extension Communication Systems, (515)
294-5168, eedwards@iastate.edu
Manage Crop Residue for Soil Conservation
AMES, Iowa -- Getting an even distribution of crop residue while harvesting is critical in stopping soil erosion throughout the coming year. According to Greg Brenneman, Iowa State University Extension agricultural engineering field specialist, farmers should think of crop residue as a renewable conservation resource.
"Residue is extremely effective in controlling erosion, and should be part of your conservation plan every year," Brenneman says. "Complete residue cover reduces erosion 95 to 98 percent, compared to unprotected soil. Any residue-straw, chaff, even the finest material, can reduce erosion by stopping rain splash erosion, slowing and trapping runoff, and allowing for better water infiltration. But it has to be in place to do it, and farmers should plan to use all of their residue for erosion protection."
According to Brenneman, the most important thing combine operators should look for is uniform distribution of crop residue. "Other than right out of the combine, there's really no way to distribute residue. So, when combining this fall, make sure you get residue spread out, whether you are working in corn or soybeans."
Combine operators need to get their equipment set up right and running right, and to be aware of how their machine best distributes residue evenly. Brenneman also says that larger heads on combines mean more concentration of material into the narrow area of the machine.
"Grain platforms up to 30 feet in width collect residue into a five foot swath. Getting that material spread back out can be difficult. And the fine material can end up in a windrow. Corn residue is heavier and a lot of corn heads do a good job of chewing up the corn stalks and dropping them back in place. But the challenge is especially great in soybeans, where essentially the whole plant goes into the combine."
Concentrated residues also can insulate the soil surface from the sun, reduce seed to soil contact, and make it tougher to plant in the spring, inhibiting crop growth next season. Brenneman says, "Some farmers think they need more tillage, but it may be that they just haven't got their residue spread out well enough. Doing a good job of chaff spreading can really help minimize the amount of tillage needed next year. And no-till farmers don't have the option of additional tillage operations to solve problems of unequal residue distribution."
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