URBANA, Ill. — A nine-year study comparing a typical two-year corn and soybean rotation with a more intensive three-year rotation involving corn, cereal rye, soybean and winter wheat found that the three-year system can dramatically reduce nitrogen — an important crop nutrient — in farm runoff without compromising yield.
The new findings are detailed in the journal Frontiers in Environmental Science.
“Subterranean drainage pipes called tiles transport nitrogen, in the form of nitrate, from fields to streams, impairing downstream surface waters,” the scientists wrote. Nitrate runoff from farms pollutes streams and lakes, some of which supply drinking water for nearby communities. Nitrates also are carried down major rivers like the Mississippi to the Gulf of Mexico, contributing to a vast oxygen-starved “dead zone.”
“For maximum crop production we need artificial drainage, in the form of tiles and ditches, across much of Illinois. Unfortunately, nitrate can be lost from the rooting zone with tile water,” said Lowell Gentry, a researcher in natural resources and environmental sciences at the University of Illinois Urbana-Champaign who led the new study with Eric Miller, a grower and landowner in Piatt County, Illinois, where the research was conducted. “Our study was designed to see if a more diverse crop rotation could reduce tile nitrate loss and still be competitive with the conventional system of corn and soybean.”
From 2015 to 2023, the researchers determined crop yield and monitored nitrate loss from tile-drained fields on a working farm. Their “control treatment” consisted of two conventionally managed fields under a corn and soybean rotation. The more intensive three-year crop-rotation system was employed on an adjacent field. This field was planted with corn, followed by a full season of soybeans, then winter wheat. A summer harvest of the wheat was followed by a second crop of soybean the same year, or double-crop soybean. Between corn and soybean, a winter cover crop of cereal rye was grown to protect the soil. The cereal rye was terminated with herbicide prior to soybean planting and allowed to decompose on the soil surface, delivering nutrients to the next crop.
Read the full article from the College of ACES.
University of Illinois Extension develops educational programs, extends knowledge, and builds partnerships to support people, communities, and their environments as part of the state's land-grant institution. Extension serves as the leading public outreach effort for University of Illinois Urbana-Champaign and the College of Agricultural, Consumer and Environmental Sciences in all 102 Illinois counties through a network of 27 multi-county units and over 700 staff statewide. Extension’s mission is responsive to eight strategic priorities — community, economy, environment, food and agriculture, health, partnerships, technology and discovery, and workforce excellence — that are served through six program areas — 4-H youth development, agriculture and agribusiness, community and economic development, family and consumer science, integrated health disparities, and natural resources, environment, and energy.