Theo Udeigwe, LSU AgCenter agronomist, is in his first year of studying the effects of different wheat residue and stubble management techniques on soil quality and soybean yield in a wheat-soybean double crop system.
Previous studies concentrated on the effects of wheat stubble management on soybean yield with less attention given to the possible long-term effects of these practices on soil quality. This is a topic of interest because alterations in soil surface covers could have a pronounced effect on soil fertility and productivity.
Burning of post-harvest residue and stubble, although associated with air and soil quality impairment, is the most commonly used technique because it results in a better seedbed to accommodate germination.
But Udeigwe’s research at the Northeast Research Station near St. Joseph, La., will consider the long-range effects of the different residue management techniques.
He planted soybeans into four different test plots after wheat was harvested -- burned, tilled, mowed, and left as standing stubble.
“I wanted to look at what happens in the long run,” Udeigwe said. “What is the effect on the soil quality indicators for each practice?”
It seems logical that burning stubble will reduce nutrients and organic matter, but the research will quantify the lost amounts among the various management techniques under study. Udeigwe needs to conduct the study for three to four years to obtain a clear picture of results.
Soybeans, the most widely grown crop in Louisiana, can be planted into a harvested wheat field to make efficient use of the land. Farmers planted 208,000 acres of wheat in Louisiana in 2011 and 1 million acres of soybeans, according to the LSU AgCenter Ag Summary.