Project ID



Investigators analyzed the impacts of liquid swine manure application, tillage, rotation and cover crops on dissolved nutrient loss in subsurface drainage. The project took place at the ISU Northeast Research Farm near Nashua. Tile drainage water samples were collected weekly for nitrate and dissolved-reactive P analysis during 2009 and 2010. Nitrate-N concentrations were highest under continuous corn receiving swine manure every year compared to other treatments. Corn-soybean rotations that received manure only before corn had lower nitrate-N concentrations compared to corn-soybean rotations that received manure before both crops. During these three years, which were not ideal for cover crop growth due to cold wet springs, nitrate concentrations in tile water from the corn-soybean system without a cover crop were similar to or slightly higher than concentrations from the corn-soybean system with a cover crop.

Principal Investigator(s)

Matthew Helmers


Ramesh Kanwar, Antonio Mallarino

Year of Grant Completion