Indiana Watershed Initiative

We are quantifying the benefits of watershed-scale agricultural conservation practices that may reduce nutrient runoff to downstream freshwaters as a part of the USDA Regional Conservation Partnership Program (RCPP) and the Indiana Watershed Initiative (IWI). We have monitored Shatto Ditch Watershed (SDW; Kosciusko Co, IN) since 2012 to assess the effects of watershed-scale planting of winter cover crops on 62-68% of croppable acres and the construction of 7 km of two-stage ditch. In Spring 2015, we added a second watershed, the Kirkpatrick Ditch Watershed (KDW; Jasper Co, IN), where we increased winter cover crop acreage to 13-32% of the croppable acres and monitored an existing 1 km of two-stage ditch. We collected water samples every 14 days from representative tile drains (n=6-25) and the base of the watershed at both SDW and KDW to quantify the effects of cover crops on nitrogen and phosphorus export. We collected soil samples from a subset of fields with and without cover crops in each watershed seasonally after cash crop harvest in the fall and before cover crop termination in the spring. Soil samples were analyzed for water extractable phosphorus, nitrate, ammonium, and soil organic matter.