Carbon is the key component in managing soil health to increase water-holding capacity and infiltration
As the world population grows, so does demand for food and the land it grows on. Farmers can keep soil healthy and productive, even under droughty conditions, by maximizing soil carbon content and minimizing soil disturbance. That was the message that Don Reicosky, U.S. Department of Agriculture Agriculture Research Station soil scientist emeritus, shared during the Growing Michigan Agriculture Conference Jan. 24 at the Lansing Center.
“Conservation of organic matter is one of the keys to improving soil health,” said Dale Rozeboom, Michigan State University Extension specialist and one of the conference organizers. “We invited Don Reicosky because we know that farmers understand the importance of being stewards of the soil if they are to get the most value from the soil.”
Reicosky’s research focuses on maintaining and improving soil health by reducing carbon loss through minimal soil disturbance. Carbon acts like a sponge for water retention and release to plants. Soil that is high in carbon is also rich in spongy organic matter, which releases nutrients and water to growing plants. Reicosky reminded growers that adding organic matter to soil will increase water retention of even sandy soils.
“If you want to manage water-holding capacity, you have to manage soil carbon, particularly during drought years,” Reicosky said. “Maintaining soil organic matter will aid in soil water retention. No-till and cover crops are the best ways to try to manage and maintain carbon in the soil.”
Reicosky said that not all no-till equipment is equally effective at carbon conservation. Through his research, Reicosky has determined that there is a measurable difference in carbon loss between low- and high-disturbance no-till drills. The amount of difference is small, but he has found a benefit to using the tillage that least disturbs the soil to keep the maximum amount of carbon in the soil.
“Tillage creates twin problems: accelerated soil degradation and accelerated soil erosion,” Reicosky said. “The No. 1 environmental enemy in production agriculture is tillage-induced carbon dioxide loss – the challenge is that carbon dioxide is invisible, colorless and odorless. Soil is a complex makeup of microbes, fungi and bacteria that require carbon to feed on.”
To retain a maximum amount of soil carbon, Reicosky recommended following three practices: minimal soil disturbance, continuous residue cover and diverse crop rotation. Dead crop residue and live crop biomass help keep carbon in the soil and help to restore soil that has been degraded by inversion tillage and crop residue removal practices. Within five to six years of continuous no-till practices, many nutrients become available in the soil that can be used as slow-release natural fertilizer.
“The future of our civilization rests on this thin layer of soil that lies beneath our feet,” Reicosky said, noting that it takes nearly 1,000 years for just 1 inch of topsoil to be created in nature. “In the future, conservation agriculture is the only option. If we want to stop erosion and save carbon, we need to park the plow.”
Reicosky was one of six professionals chosen by Michigan State University Extension to discuss important concepts necessary to keep Michigan agriculture on a growth curve. You can see his suggestions for managing soil health, as well as other presentations by experts from across the country, on the Michigan State University Extension website, www.msue.msu.edu. Click on “Agriculture” and look for “Growing Michigan Agriculture Proceedings” in the Resource channel in the lower right section of the site.