The cropland in the Midwest is among the most productive in the world, but only if adequate drainage is provided. Drainage reduces soil compaction, makes it easier for farm machinery to work the land and decreases crop damage from excess moisture.
Much of the region uses underground pipes or “tiles” to channel excess water from the field. Nitrogen, phosphorous, and bacteria can make their way into tile drainage systems and enter lakes, rivers, and groundwater. This pollution can be harmful to humans and can create “dead zones” where aquatic life cannot survive.
A team of 22 Land-grant University researchers are working with USDA scientists and industry partners to develop new technologies and strategies that improve drainage. The project’s strong Extension component has increased farmers’ knowledge and confidence about drainage management and provided valuable information to industry professionals, educators and policymakers.
Benefits of Drainage Management
Improved drainage management could significantly reduce water quality problems and related environmental and human health risks. Furthermore, improved drainage can boost crop yields and reduce variability from year to year, providing a more stable source of food for consumers and predictable profits for farmers.
Researchers designed better drainage structures, such as bioreactors, saturated buffers, wetlands and vegetated ditches, which are placed at the edge of fields to filter drainage water. Many of the new structures use automation and other “smart” features to help farmers fine-tune drainage management and minimize time, labor and costs.
Researchers recommended effective practices, such as planting living mulch, winter cover crops, perennial grasses and other land covers, using lower fertilizer application rate, and avoiding fertilizer applications on wet ground and when rain is forecast within 24 hours.
Confined animal feed operations are paying more attention to vulnerable drainage outlets and adjusting manure application methods, rates, and timing, accordingly.
New models help farmers make smart drainage management decisions. The group’s drain spacing calculator has been used in 44 countries and 36 states. Better drainage models also help scientists and farmers monitor water quality and prepare for the ways climate change will affect agricultural drainage.
The U.S. EPA’s Mississippi River/Gulf of Mexico Hypoxia Task Force used the group’s recommendations to develop strategies for nutrient reduction. Between 2011 and 2017, farmers in the 12 states on the task force installed 32 denitrifying bioreactors and implemented drainage water management on more than 40,000 acres, preventing over 300,000 pounds of nitrate from entering the Mississippi River.
The group’s research also laid the foundation for three new USDA-NRCS conservation standards that detail design specifications for edge of-field drainage management structures. With conservation standards in place, farmers can now apply for cost sharing, and interest in these practices has increased dramatically.
Scientists demonstrated the potential of bioreactors in spring applications with a pilot-scale system that achieved over 40% nitrogen removal. The “pay for demonstrated performance” project implemented bioreactors to treat legacy nitrogen in springs and explored mechanisms to incentivize agricultural landowners to treat the largely neglected issue of legacy nutrients in cost-effective ways.
The Transforming Drainage project, led by Purdue University, continues to support collaboration to understand and implement storage of drainage water in the environment. The establishment of the research database has enabled and strengthened the informational and technological infrastructure to allow for the characterization of impacts on agricultural production and environmental benefits that come from storing water on the landscape.
NCERA-217 is funded in part by the Multistate Research Fund through USDA-NIFA and by grants to project members at the following institutions: Cornell University, University of Georgia, University of Illinois, Iowa State University, University of Kentucky, Michigan State University, University of Minnesota, University of Missouri, North Carolina State University, North Dakota State University, Purdue University, South Dakota State University, and Virginia Polytechnic Institute and State University, along with the USDA-ARS and USDA-NRCS. Learn more: bit.ly/NCERA217.
Top image: Example of water management practice. Improved drainage management could significantly reduce water quality problems and related environmental and human health risks. Image courtesy of Lynn Betts, SWCS. NRCS.