You may not have to settle for yield drag with continuous corn. Recent University of Minnesota research indicates that yields from continuous corn in conservation tillage may be comparable to corn following soybeans or intensive tillage when selected management and products are used.
One method entails 2 gallons per acre of ammonium thiosulfate (ATS) 12-0-0-26 and 7 gallons per acre of urea-ammonium nitrate (UAN) 28 percent dribbled over the row after the seed furrow has been closed. This can be applied with or without an in-furrow starter treatment, such as 4 gallons per acre of ammonium polyphosphate (APP) 10-34-0.
"The dribble treatment really gets continuous corn off to a good start, especially in years with wet and cool early season conditions,” says Jeff Coulter, Minnesota Extension agronomist. "Plants get built up, so they don’t experience the early season yellowing and stunting and they typically reach maturity a little earlier."
Soil scientist Jeff Vetsch led the study on fine-textured glacial soils at the Southern Research and Outreach Center, Waseca, Minn. While 2013 plots had not yet been harvested when Corn+Soybean Digest spoke to Coulter, he was very positive about what he saw. "Our cold, wet spring was not conducive for good root growth," he says. "Standard continuous-corn acres looked tough, but plots with the surface dribble treatment looked better. Some area farmers adopted the practice this spring, and they were pleased with the early-season results. We look forward to seeing the yield data."
The practice has its challenges, Coulter says. Dribbling on the ATS and UAN at planting slows that process. However, field maps and GPS would allow for a separate trip.
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"For the most part, growers in these soils are putting on sulfur anyway," Coulter says. "This method concentrates it where the plant needs it."
Coulter suggests these early results are just the first step in improved yields. He and Vetch are coupling the method with residue management and longer-season hybrids with higher populations.
"Growers know they can get higher yields with longer-season hybrids, but in cool years they are wetter at harvest," he says. "Getting the corn off to a faster start helps it reach maturity more quickly."