His research projects primarily explore nutrient management, cycling, and distribution within soil profiles and across landscapes. Part of this research is investigating ways to increase the efficiency of phosphorus applications in agriculture, with a main goal of increasing food production while reducing phosphorus runoff into surface waters. Dr. Nelson’s work with KCARE resulted in the development of the Kansas Agricultural Watershed Field Laboratory, a large in-field water quality laboratory at the Ashland Experiment Farm near Manhattan. This facility is used to investigate effects of agricultural systems on surface water quality and develop and verify best management practices to reduce non-point source pollution from agricultural lands.