It’s well known that the ability of no-tilled soils to retain more moisture can pay off in drought years, but the practice can also beat out conventional tillage when there’s too much water.
Purdue University agronomist Tony Vyn and research agronomist Terry West were surprised to find that despite excessive rain and cool temperatures this spring, no-tilled corn yields outperformed chisel-plowed yields in both continuous corn and a corn-soybean rotation in their long-term tillage plots near West Lafayette, Ind.
The researchers found corn yields were 11 bushels per acre higher than fall chisel plow and spring secondary tillage, when corn followed soybeans, and 5 bushels per acre better in continuous corn.
“Most of the reason for that is the improved soil structure in long-term no-till vs. the chisel plow system — a system where we did secondary tillage with soil a little wetter than we wanted, simply so that we could accomplish planting by May 23,” the researchers say.
The research site received more than 10 inches of rain in June and 7-plus inches in July. Soils are silty clay loam with about 4% organic matter, and while naturally poorly drained are systematically tiled.
Vyn and West note that normally, no-tilled corn yields equal to the fall chisel-plow system in a corn-soybean rotation, but in continuous corn it’s usually about 7% lower — even when no-till plots are managed as best as possible.
These results may provide reassurance that no-till can maintain or increase corn yields compared to the common fall tillage system, the researchers say.
It also confirms the benefits of rotating corn with soybeans when weather conditions are unfavorable, as this year’s continuous-corn yields averaged 17% lower than corn that was in a rotation with soybeans.