If farmers leaving Roger Wenning's farm from a field day recently took away only one message, it should have been that placing each corn seed at the same depth into the same soil conditions is one of the secrets to high yields. It's important in any tillage system, but especially in no-till.
"The environment in a no-till situation at planting time can change dramatically in terms of both temperature and moisture content by each half-inch depth into the soil," says Barry Fisher, state agronomist for the Natural Resources Conservation Service. "The goal is doing everything you can to make sure that each seed winds up in the same one-half inch zone."
Fisher made the comments while walking farmers through an actual no-till planter, showing how he preferred to set it up to accomplish that task. The event was sponsored by the Decatur County Soil and Water Conservation District, with help from other conservation districts in the area.
"When seeds are not in the same conditions, they don't germinate at the same time," Fisher explains. "Seedlings that emerge late will likely be barren. They won't be producing an ear. We need every plant to produce a good ear if we're going after the type of super-high yields we've been hearing about that some no-till farmers across the country are achieving."
Getting consistent depth starts with paying careful attention to each row unit on the planter, he says. He says no-till coulters aren't essential in most no-till systems these days. However, if you choose to use one, make sure it doesn't run deeper than the seed discs where the seed is delivered. "Once it runs deeper, then you have no idea where that seed is winding up," he says. "You don't know what depth it will be at, and you don't know if it's surrounded by soil or an air pocket."
In addition, coulters running deep tend to pull up wet soil. The deeper you go below the surface, especially in no-till situations, the wetter the soil. Fertilizer openers if not set correctly can also chunk up wet soil. In either case this soil can adhere to gauge wheels and begin to affect depth placement.
Fisher prefers floating row cleaners. "Let them float and don't let them run too deep," he says. "Replace them when the points get narrow and sharp. Otherwise, they begin digging in and running too deep, and you're again not going to be doing the job you need to do if you're after consistent seed placement."