Impact of Reservoir Tillage on Runoff Quality and Quantity

The effects of reservoir tillage on runoff and water quality were studied under two levels of soil compaction in the production of cotton. A wide frame tractive vehicle was used during plot establishment and during all farm operations to provide the desired soil compactions. LEPA (Low Energy Precision Application) irrigation was used to apply supplemental water as required. Runoff quantity was monitored with flumes and runoff samples were taken using Coshocton-type runoff samplers. Thirteen runoff events were monitored and analyzed over a two-year period for the replicated, four-treatment study. Reservoir tillage decreased runoff and total discharges of organic nitrogen and phosphate. Differences in concentrations of water quality parameters (total solids, ammonium, total kjeldahl nitrogen, nitrate, phosphate, and COD) were not statistically significant. Although not statistically different, total runoff and total discharge of water quality parameters (except phosphate) were lower for the low compacted treatments compared to the high compacted treatments.