Objectives of the Study:

1. To determine the impacts on water quality of recommended application rates of swine manure, based on nitrogen uptake requirements of crops.
2. To study the long-term effects of over-application of swine manure on nitrogen leaching to groundwater.
3. To study the long-term effects of spring and fall injection methods of swine manure application on crop yields, and nitrogen, in surface runoff and shallow groundwater.
4. To develop and recommend appropriate manure and nutrient management practices to reduce the water contamination potential from manure and UAN applications and enhance the use of swine manure as an alternative to the use of inorganic fertilizers for Iowa's sustainable agriculture.