BIO: Antonio P. Mallarino is Professor of Agronomy, Soil Fertility Research and Extension Specialist, at Iowa State University. He began his career at the University of Uruguay in 1976 and joined the Iowa State faculty in 1993. He develops research and extension programs related to agronomic and environmental issues of nutrient management with emphasis on phosphorus, potassium, and liming. Issues addressed include soil and plant-tissue sampling and testing, fertilizer placement methods, use of variable-rate technology, and phosphorus management impacts on water quality. He has published more than 50 scientific articles and 200 technical/extension articles. Mallarino oversees the Iowa State University Soil and Plant Analysis Laboratory, represents Iowa at the regional USDA-CSREES committees Soil Testing and Plant Analysis for the North Central Region (NCERA-13) and Minimizing P Losses From Agriculture (SERA-17/IEG), represents the NCERA-13 at the oversight committee for the North American Proficiency Testing Program (S890), has served as Associate Editor of Agronomy Journal and Soil Science Society of America Journal, and is Fellow of the American Society of Agronomy and the Soil Science Society of America.