The underground drainage systems that criss-cross much of the U.S. Corn Belt are about to get a major overhaul to improve both farm efficiency and the environment.
The upgrade is important because the same pipes that deserve a lot of credit for America's agricultural bounty bear some of the blame for carrying nitrates, phosphorus and other pollutants to waterways such as the Gulf of Mexico.
Norm Fausey leads the Agricultural Research Service's Drainage Research Unit at Columbus, OH. He and ARS agricultural engineers Kevin King and Barry Allred, along with Ohio State University-Columbus scientist Larry Brown, are now in the sixth year of running drainage management studies in northwest Ohio.
Drainage management is a new system of draining water only as needed for planting and growing crops. Currently, most drainpipes just drain continuously year-round. With drainage management, control structures allow farmers to raise or lower the water table in various fields as conditions warrant. This even gives farmers the option of letting farm fields provide wetland functions and wildlife habitat for birds and ducks during the non-growing season. ARS serves on a task force called ADMS, for Agricultural Drainage Management Systems, that is promoting the field drainage upgrade. The task force's members are banking on the concept of drainage management to reduce nitrate losses by at least 30% while draining 40-60% less water. Those numbers, recently reported by the ADMS task force, come largely from research findings in Illinois, North Carolina and Ohio.
ADMS is also considering the idea of creating new wetlands alongside crop fields to filter contaminants from drainage water. Farmers could store the filtered water in a reservoir for later reuse during drier parts of the growing season. Fausey has designed such a system, called a Wetland Reservoir Subirrigation System. He has seen these reuse systems raise corn yields by more than 45% and soybeans by about 40% in dry years.
Read more about this research in the September 2005 issue of Agricultural Research magazine, available online at: www.ars.usda.gov/is/AR/archive/sep05/drainage0905.htm.