Advances in genetics and traits promise to accelerate yield increases in U.S. corn and soybeans. Some even say yields will double by 2030. But what’s often missing from the conversation is the critical role of soils.
Soil scientists remind us that even the most elite crop varieties need well-managed soils to provide the nutrients and water essential for high yields.
“U.S. corn and soybean farmers already are feeding whole nations,” says Jennifer Shaw, head of sustainability with Syngenta. “As we coax even more yield from every acre, soil health will become just as important as crop health in our drive to double food, feed and fiber production.”
Soils in the Corn Belt are among the world’s most productive, but they are degrading at a rate that will affect productivity unless we reverse the trend, points out Kendall Lamkey, agronomy chair with Iowa State University. Despite major gains in soil conservation, Iowa leads the nation in soil loss by water. Illinois is a close second.
“It’s hard to really appreciate just how good our ground is until you’ve seen farmers in developing countries trying to grow a crop in soil that has been severely eroded and depleted of organic matter,” Lamkey says. “What we have is a very precious natural resource that needs to be maintained and nurtured so that it can keep producing at the levels we expect.”
Saving soil, toil and oil was a popular rallying cry of the 1980s conservation-tillage movement. Syngenta legacy companies played a major role, helping to replace tillage with weed-control technologies like Gramoxone Inteon herbicide and supporting creation of the Conservation Technology Information Center (CTIC).
“The goal of programs like T by 2000 was to reduce soil erosion to a level where the rate of soil loss would be equal to or less than the rate of soil replacement,” Shaw says. “Now the focus has expanded from saving soil to improving soil.
"We need the foundation of a healthy soil to bring plant potential to life.”
Building organic matter
“Anytime soil moves, I call it dirt because we lose the organic matter and micro-organisms that make soil a living, breathing and very productive natural resource,” Lamkey says.
Tillage also takes a toll on organic matter in flat ground, points out Jerry Hatfield, director of the National Laboratory for Agriculture and the Environment.
Every time we till the soil, we release carbon and lose organic matter, he explains. To support the yield potential of advanced traits and genetics, soil advocates recommend reducing or eliminating tillage to maximize carbon storage.
“Carbon may be bad for the atmosphere, but it’s very good for our soils,” Hatfield says. “It’s the major ingredient in organic matter and the glue that holds soil together and makes it work better.”
Organic matter absorbs up to six times its weight in water and holds up to five times more nitrogen than clay. It improves water infiltration and holding capacity, encourages root growth and minimizes yield reductions from short-term weather extremes, like heat, drought or driving rain.
“Improving water infiltration is especially important in the Midwest because weather patterns here are trending to less frequent, but more intensive, rainfall events,” Hatfield says.
Through a combination of carbon management practices, including conservation tillage, he says growers can improve crop productivity within 3 to 5 years.