Preliminary Nitrate and Dissolved Phosphorus Removal from a Saturated Buffer in Illinois.

Agricultural producers farming the 9.7 million acres of tile-drained land in Illinois need a wide variety of proven options to reduce nitrogen loss. The practice of a saturated buffer may reduce tile drainage nitrogen loss, but is not included as a recommended practice in the Illinois Nutrient Loss Reduction Strategy (NLRS). A saturated buffer is a modification of the edge-of-field drainage system that allows drainage water to flow as shallow groundwater through a buffer’s soil. In a saturated buffer, a perforated drainpipe extends laterally along the riparian buffer and is connected to the drainage main via a control structure. This control structure forces drainage water sideways into the perforated drainpipe, so it can seep through the buffer where the existing vegetation and native soil microbes uptake and process both the water and the nitrate in the water. The goal of this work is to evaluate nitrate-nitrogen loss reduction provided by saturated buffers to assess their potential inclusion as recommended practices in the NLRS. Preliminary Illinois saturated buffer nitrate and phosphorus removal results will be presented here. The total volume of water treated by each saturated buffer will be assessed via a pressure transducer and v-notch weir used in a control structure, and water levels and nutrient dynamics will be evaluated in sixteen wells (four transect of four wells each) distributed along the length of the buffer. The ultimate goal is to provide producers in Illinois practical options to reduce nitrogen loss through tile drains, while maintaining high crop yields.