Effects of Conservation Practices On Mississippi River Basin Initiative Watersheds in Missouri.

Agricultural practices are often criticized for Non point source pollution of water bodies.  Mississippi River Basin Watershed Initiative (MRBI) was initiated to evaluate effects of conservation practices on water quality of first order row crop watersheds in Missouri.  The study design consisted of 10 watersheds under corn/soybean rotation with terraces, cover crops, crop rotation, grass waterways, and nutrient management treatments.  Sequential water samples were collected after runoff events and samples were analyzed for sediment, total nitrogen (TN), nitrate, total phosphorus (TP), and dissolved phosphorus (DP).  Sediment and nutrient losses were significant lower as compared to pre-treatment losses.  Installation of terraces reduced the runoff volume on all watersheds.  However, nutrient losses varied among watersheds.  A watershed with multiple conservation practices showed significant reductions in all NPSP. The results of the study showed that establishment of conservation practices on agricultural watersheds reduce NPSP losses to water bodies.