The Nebraska Environmental Trust has awarded a grant to construct a subsurface drip irrigation system that uses feedlot effluent to irrigate crop fields. The practice will be evaluated as a potential means to better manage the state's limited water resources, an ongoing research priority of the University of Nebraska.

The irrigation system is under construction at the university’s Mitchell Agricultural Laboratory, site of the feedlot and research plots, said Xin Qiao, irrigation and water management specialist and the principal investigator on the project. The Mitchell Lab is five miles north of the Panhandle Research and Extension Center in Scottsbluff.

Water that runs off the 105-pen feedlot into an effluent holding pond will be pumped through the subsurface drip system to irrigate crop research fields, Qiao said. On some plots, air will be added to water by injecting it into the drip irrigation system to test its effect on water quality and crop yield.

The plots will be divided into two sections, one planted to sugar beets and the other to corn, and 20 zones (10 in each section). Half of the zones will have air injected. Soil samples and water samples will be collected and tested for quality.

The Nebraska Environmental Trust grant provides $287,605 for the two-year project, which begins this spring. The project is a collaboration between the Panhandle Center and work by Matteo D’Alessio and Chittaranjan Ray at the Nebraska Water Center.

Underground emitter tape is being installed in the fields this week, and other equipment, such as controllers and air injectors, is expected to be installed in early May. Mazzei, a California company that manufactures the injectors, is providing the injectors at cost, Qiao said.

Re-use of wastewater is one option for making optimal use of limited water resources. In the North Platte River Basin, a moratorium on irrigation expansion and allocations on irrigation water have been in effect for years, with the goal of reducing streamflow depletions caused by irrigation water pumping. Wastewater could be an alternative source of irrigation water.

The outcome of this study may provide a best-management practice to treat feedlot runoff and increase crop yield for corn and sugar beets in western Nebraska, Qiao said.