Clay soils can make you wonder why you're farming. But treat them right, and they may crank out profitable crop yields.
So if you've been fighting stubborn clays and losing, listen up.
August droughts, limited water intake and shallow crop rooting may not be mission-impossible problems.
Subsoiling tests on several eastern Arkansas clays have produced some startling numbers. Tony Wilkie of Forrest City, AR, can tell you about them.
Wilkie, who farms 2,365 acres of soybeans, rice and wheat, is a cooperator in the University of Arkansas Soybean Verification Project. He noticed years ago that his dryland bean fields often died before maturity in the seasonal August drought. But there were also numerous small "islands" of still-green plants sprinkled in those same fields. He tried to fix the problem by turning 600 acres with a subsoiler in the spring.
"I determined it was costing too much, tearing up my tractor, and I couldn't tell any difference in the crops," says Wilkie. "I sold the plows."
Two years ago, while conducting other verification trials on his farm, Wilkie and ag engineer Gary Huitink, decided to subsoil random strips in some stands of dying dryland beans.
"That was August, and we just plowed a couple strips through the fields and kind of forgot about it," recalls Wilkie.
As usual, the beans began to die in August the following year -- all except the subsoiled strips, which grew at the same rate as the nearby irrigated beans. Wilkie called Huitink and said, "I think we have something here."
Careful measuring of the subsoiled strips at harvest showed yield increases of 3 bu/acre on Sharkey clay and an astounding 25.2 bu on Earle clay (from 17.9 to 43.1). Wilkie's irrigated beans in the same field came in at 38 bu/acre that year.
Huitink continues field testing on several types of clay. He emphasizes that subsoiling isn't the answer for all clay soils. About a 3 bu/acre yield increase is necessary to make it an economically sound practice, he says.
"So far, our testing suggests that certain clay soils are most responsive with the 9 to 12" subsoiling done in the fall to catch and store the winter rain," explains Huitink.
The Arkansas Soybean Promotion Board is funding research to identify soils most responsive to subsoiling. Other studies are ongoing in Mississippi, Louisiana and Ohio.
Wilkie thinks his land can benefit from subsoiling. He bought a DMI subsoiler and leased a Caterpillar Challenger tractor for the several hundred acres he plans to treat in the next few years.
"Subsoiling will buy me 10-12 days of drought tolerance on early planted Group IV beans," he says.