Nutrient Distribution from Subsurface Drip Irrigation System Using Swine Effluent.
Lisa Fultz, Oklahoma State Univ, Plant & Soil Science Dept, 606 E Redbud 134J, Stillwater, OK 74075
Concerns’ regarding utilization of animal waste in agriculture has led to the use of systems such as subsurface irrigation to minimize contact with the waste. However little is known about the movement and distribution of nutrients applied via subsurface irrigation systems. The purpose of this study is to determine the distribution of constituents found in swine effluent when applied through a subsurface drip irrigation system located on the Panhandle Research Station in Goodwell, Oklahoma. Suction lysimeters were used to collect solution samples at and between emitters on the inlet and distal ends of a single lateral. Solution samples were obtained from fields with application rates of 2.38 L/h (0.63 gph) and 0.72 L/h (0.19 gph) respectively. Samples taken prior to swine effluent application were used to determine any background levels from previous effluent applications. Samples drawn immediately prior to and within one day following each effluent application were used to determine the distribution and movement of nutrients. Analysis for pH, electric conductivity, orthophosphates, nitrate-nitrogen, ammonia-nitrogen, copper, zinc, and calcium was preformed on each sample. Flow from the inlet to distal end within the high rate application does not appear to be uniform; however this does not seem to be the case for the low application rate. The distribution of nutrients indicated that the majority of the nutrients were located in close proximity to the emitter with concentrations decreasing with distance.