IMPACT OF RESERVOIR TILLAGE ON RUNOFF QUALITY AND QUANTITY

The effects of reservoir tillage on runoff and water quality were stud ied under two levels of soil compaction in the production of cotton. A wide frame tractive vehicle was used during plot establishment and du ring all farm operations to provide the desired soil compactions. LEPA (Low Energy Precision Application) irrigation was used to apply suppl emental water as required. Runoff quantity was monitored with flumes a nd runoff samples were taken using Coshocton-type runoff samplers. Thi rteen 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. Differ ences in concentrations of water quality parameters (total solids, amm onium, 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 phosph ate) were lower for the low compacted treatments compared to the high compacted treatments.