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When a no-tiller buys farm ground in some locations, such as the lake plain of northwest Ohio dominated by heavy clay, there isn’t much hope of changing the soil’s texture or mineralogy.
But there are properties related to how soil particles arrange and create soil structure that are sensitive to management. Soil amendments, such as gypsum, show promise for improving these difficult soils, says Dr. Jerry Bigham, a soils researcher and former director of Ohio State University’s School of Environment and Natural Resources.
In ideal soil, half the volume is comprised of minerals and organic matter, while the other half is pore space that serves as the ventilation and irrigation system for the soil profile.
Ideally, about half of the pore space should be water, which creates optimum conditions for growing crops. But if too much water floods the pores, there’s a rapid decline in microbial activity and crop response.
“The diffusion of oxygen needed for plant respiration is about 10,000 times slower through water as opposed to air,” Bigham says. “Compaction alone can reduce this pore space by 20%.”
Air-water balance is the single-most-important factor limiting U.S. production agriculture, he adds. According to a 2006 Iowa State study, the top two causes of economic loss to U.S. agriculture between 1980 and 2004 — looking at major events of $1 billion or more — were combined heat and drought stress at $130 billion and flooding and water logging at $50 billion.
If more farmers paid attention to…