Technical Abstract: Farmers will adopt alternative management systems to improve water quality more readily if they understand how those management alternatives affect the release of contaminants, crop yields, and ultimately, their net income. We propose a method to address these issues by integrating observed data from field experiments, a comprehensive simulation model, review by local experts, and application through a decision support system by technically trained conservationists. Fourteen years of observed data from 30 research plots on the Northeast Research and Demonstration Farm near Nashua, Iowa were used to calibrate the Root Zone Water Quality Model (RZWQM) to simulate the effects alternative management systems on crop yields and N loadings into tile drains. An Expert Panel reviews the simulations and the long term average annual management effects. Those management effects, as well as the daily values of variables that describe the crop growth and nitrogen loading in tile flow processes, are put into a database. As part of the conservation planning process, farmers would use a decision support system with the database, under the guidance of the Natural Resources Conservation Service, to select management systems that meet the farmers' goals while reducing water quality problems.