Subsoiling can help improve yield potential of certain poorly drained soils, a six-year study by ag engineering researchers at Ohio State University (OSU) shows.
Corn and soybeans grown on subsoiled plots yielded about 5 percent more than crops grown on nonsubsoiled ground during a study begun in 1991 at the Ohio Agricultural Research and Development Center in northwest Ohio.
According to OSU ag engineer Randall Reeder, long-term data showed corn yielded 110 bushels per acre or about 5 bushels per acre more than non-subsoiled plots. Soybeans yielded 35 bushels per acre or almost 2 bushels per acre more than nonsubsoiled plots.
Using typical corn and soybean prices, the yield increases would return about $2 for every dollar spent subsoiling, he says.
“There are a lot of subsoilers used in northwestern Ohio,” Reeder says. “If it didn’t pay, there wouldn’t be that much subsoiling going on.”
Researchers used 10- and 20-ton grain carts to compact every square inch of soil three years in a row on plots at study sites.
After the compaction, yields drastically declined compared to non-compacted plots. The 10-ton plots recovered naturally by 1992, but the 20-ton plots did not return to normal yields until 1997.
Starting in 1991, Reeder subsoiled some compacted and non- compacted plots every two years. Subsoiling helped repair the compaction damage and helped yields on non-compacted plots.
The 1997 data showed corn and soybean yields on subsoiled plots were 5 percent and 2 percent higher, respectively, than on non-subsoiled plots. Soybean yields on subsoiled ground were 52 bushels per acre compared to 51, while corn yields on subsoiled ground were 125 bushels per acre compared to 119.
The study was conducted on Hoytville silty clay loam soil, a poorly drained soil common in northwestern Ohio, Reeder says.
“On that soil in particular, there’s a benefit to deep tillage (subsoiling) even if the soil hasn’t been compacted,” Reeder says. “Our data shows it would pay to subsoil every two years even if you don’t have compaction.”