Comprehensive soil and nutrient management on the farm can reduce water pollution. Matching the amount and timing of nutrient applications to the needs of crops is the most cost-effective and efficient way to control nutrient contamination of surface and ground water. Soil conservation practices reduce surface-water pollution, but can increase nitrate leaching through the soil. Misdirected practices, such as excessive or mistimed manure applications, can increase nutrient contamination of surface and ground water. This report uses a field-scale computer simulation model, CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems), to assess pollutant losses from agricultural land to water. A central theme of the analysis is the tradeoff between nutrient loadings in surface water versus ground water.