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No-tillers growing continuous corn often face a dilemma when residue piles up in their fields after harvest, leaving a mat that can keep soils cold and wet and make planting difficult.
For some farmers, one option could be removing some stover for cellulosic ethanol production. But that raises another question: How much residue can be removed before negatively impacting the level of nutrients and organic matter in no-till soils?
Research and agri-business experts say a number of factors affect this decision, but there can be a happy medium for no-tillers if some guidelines are followed.
Three Critical Issues. With corn-stover removal, the three critical issues to factor in are soil erosion, fertility values of the stover and soil organic matter, says Andy Heggenstaller, Pioneer Hi-Bred’s agronomy research manager for cellulosic ethanol in Johnston, Iowa.
“If we manage stover removal to sustain the organic matter in the soil, then enough residue will be left so that soil erosion should not be a problem,” Heggenstaller says. “In fact, leaving that level of stover should be more than enough to protect the soil.
“If we know how much fertilizer, such as nitrogen, phosphorus and potassium, that we’re removing with the corn stover, that just becomes part of the economic-value consideration for the farmer.”
Yield, tillage and crop rotation affect how much stover can be removed, Heggenstaller says. Based on Pioneer’s research and other studies, the company believes that corn fields that yield at least 175 to 180 bushels per acre are productive enough…