Water Table Management to Enhance Crop Yields in a Wetland Reservoir Subirrigation System

A Wetland Reservoir Subirrigation System (WRSIS) allows for capture, treatment, storage, and reuse of runoff andsubsurface drainage waters from cropland, in turn providing both environmental and agricultural production benefits. Thethree WRSIS sites presently in operation are all located within the northwest Ohio portion of the Maumee River Basin andhave been in use for five to six complete growing seasons. WRSIS components include an underground drainage pipe networktied to both a constructed wetland and a water storage reservoir. With this type of system, the drain pipes can be used atdifferent times to either add water (subirrigation) or remove water (subsurface drainage) from the root zone, therebyenhancing crop yields, especially in dry years. Obtaining these crop yield benefits requires a proper water table managementapproach that includes practicing suggested operational guidelines and initiating as needed system modificationimprovements. By incorporating a proper water table management approach, and in comparison to control plots, WRSISsubirrigated field crop yield increases for corn and soybeans, respectively, were 34.5 and 38.1% during drier growing seasons,14.4 and 9.7% during near average to wetter growing seasons, and 19.6 and 17.4% overall.