"We are seeing an awful lot of tillage occurring in Iowa this fall," observes Barb Stewart, state agronomist for USDA's Natural Resources Conservation Service. "Some farmers are making more than one pass. They say they are having trouble with a build up of too much crop residue.
"I want to remind farmers they don't have to do that much tillage," says Stewart. "It's expensive, it wastes energy and it opens the land up for soil erosion and runoff which impairs water quality in our streams, rivers and lakes."
Tillage in the fall creates several problems in addition, she adds. "The more you till the soil the more you destroy the soil structure. You may get a boost in yield that first year following fall tillage, when those microbes are releasing the nutrients for the crop. But in the long-run, you'll be hurting yourself."
Do tillage in spring or use no-till or strip-till
There are a few exceptions such as on heavy ground--the gumbo soils in bottomland. "But as a general rule, farmers in Iowa can get most of the tillage work done in the spring if the ground needs to be tilled," says Stewart.
"We advise farmers to do their tillage in spring or consider some of the options such as no-till or strip-till," she adds. "The corn seedling tends to be a weaker seedling than a soybean seedling; corn isn't as robust when it comes to getting started in the spring. Sometimes corn needs a little extra help to get it up and out of the ground. Instead of tillage, I suggest farmers use row cleaners on the planter to get the crop residue off the row where the seedling will be coming up."
Using row cleaners to leave a clean strip of dark soil to plant the seed into will help warm the strip of soil up a little faster and assist the seedling in getting up and growing. Row cleaners on a no-till planter really help to make no-till work.
Do you need to till for corn on corn?
If you feel like you really must till the ground, use strip till, advises Stewart. Tilling that strip in the fall, right over the row, can be a big help in getting the seedling up in the spring when you plant and yet fall strip till can still provide a lot of the benefit of the straight no-till. The improved soil structure, soil quality and leaving that crop residue on the soil surface in between the rows are big benefits in improving and protecting the soil.
Some farmers say they are doing more tillage than usual this fall because they are going to plant more corn-on-corn acres next spring. That means planting corn into cornstalk residue, which is harder than planting corn into bean residue. "These farmers want to bury more crop residue to give the corn a better chance at emerging and getting a strong, fast start next spring," notes Stewart. "But I advise farmers to get a good set of row cleaners for their planter and avoid having to do so much tillage, especially fall tillage."