GREENSBORO, NORTH CAROLINA - 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," says Lamkey. "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."
Raising the bar
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(R) 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," says Syngenta's Shaw. "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."
To help raise awareness of soil's role in feeding the world, Syngenta recently co-sponsored "Dig It! The Secrets of Soil," an exhibit at the Smithsonian's National Museum of Natural History. In the field, Syngenta continues to champion conservation tillage through advances in genetics, traits and crop protection, as well as stewardship of glyphosate-tolerant technology.
"Glyphosate gives us a very cost-efficient way to meet the challenge of weed control with low or no tillage, but the emergence of glyphosate-resistant weeds threatens to take this very valuable tool away from us," says Chuck Foresman, manager of weed resistance strategies with Syngenta. Some farmers in the South are reverting back to tillage as the only available alternative for controlling glyphosate-resistant horseweed and Palmer amaranth.
"This is the worst-case scenario and it's exactly what we're trying to avoid with our Resistance Fighter(TM) program," says Foresman. "The goal is to keep glyphosate-tolerant technology viable through the use of Resistance Fighter brands that incorporate multiple modes of action." These include Gramoxone Inteon across all row crops at burndown and Halex(R) GT, Lumax(R) and Lexar(R) herbicides for corn; Prefix(R) , Boundary(R) and Flexstar(R) GT herbicides for soybeans; and Reflex(R) and Sequence(R) herbicides for cotton.
Without management changes, Foresman says around 39 million row crop acres could be infested with glyphosate resistant weeds by 2013, leading to increased tillage and soil loss. (See www.resistancefighter.com for more information.)
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," says Lamkey.
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," explains Hatfield. "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," notes Hatfield. Through a combination of carbon management practices, including conservation tillage, he says growers can improve crop productivity within three to five years.