Dr. Donald (“Don”) R. Nielsen was a pioneer and leader in the recognition of close linkages between agronomy and the hydrologic and environmental sciences, beginning in the 1970’s. His work on solute transport in unsaturated soils and on the role of soil heterogeneity on infiltration and contaminant transport helped launch a revolution in hydrologic thinking.
Born in Phoenix, AZ, in 1931, he completed his BS degree in agricultural chemistry in 1953 at the University of Arizona, where he also earned his MS degree in 1954. In 1958, he received his Ph.D. degree working with Don Kirkham at Iowa State University.
He then spent the rest of his career at the University of California, Davis where, in addition to advising graduate students and international visitors, he helped develop graduate degrees in hydrology and earth sciences. He served the University as chair of both the Department of Land, Air and Water as well as the Department of Agronomy and Range Science, while also being Associate Dean of the College of Agriculture and Environmental Sciences. His service to our profession was profound. He has been the president of the Soil Science Society of America, and the American Society of Agronomy. He also served as president of the Hydrology Section of the American Geophysical Union as well as serving as president of the Soil Physics Commission of the International Society of Soil Science. He has served on the Board on Agriculture of the National Research Council NCR, served on panels of Remote Sensing for Soil and Water Resources of the Space Applications Board of NRC and the Geophysics Board of Water Resources Review Committee of the Food and Agriculture Board of the National Academy of Science. Presently he is a member of the China Committee of NRC. He served as Editor of Nitrogen in the Environment, Associate Editor, 1974-84, and Editor, 1984-88, of Water Resources Research and Associate Editor, 1974-90, of Outlook in Agriculture. He also has served on Editorial Boards of Irrigation Science and Agronomy Journal. Presently he serves on Editorial Boards of Journal of Soil Science, Soil Science, Soil Tillage Research, Journal of Ecological Modeling, Catena, Soil Technology, Trends in Agricultural Science and Journal of International Agrophysics. He also has served as consultant for the U.S. Army, NASA, California Department of Water Resources, California Department of Education, USEPA, FAO, USAID and USDA. He has participated in the review of several university departments for Cooperative Research and Agricultural Research Service units of the USDA. While on sabbatical leave, he served as consultant to the International Atomic Energy Agency, Vienna, 1974-75. He has served as a member of Board of Directors of the U.S. National Institute for Global Environmental Change, and served on the Board of Directors, College of Soil Physics, International Center for Theoretical Physics, Trieste, Italy, as well as on the Budget and Finance Committee of SSSA.