Nicola Senesi, PhD, FSSSA, FASA, FPSSS , is Professor of Soil Chemistry and Head of the Department of Agroforestal and Environmental Biology and Chemistry of the University of Bari, Bari, Italy, where he has been actively involved in research and teaching since 1969. He was conferred a doctorate honoris causa by the Institut National Polytechnique de Toulouse, France, in 2000. He has edited ten books and published over 250 scientific refeered articles and book chapters. Baoshan Xing, PhD , is Professor of Environmental and Soil Chemistry at the Department of Plant, Soil, and Insect Sciences, University of Massachusetts Amherst, where he has been actively involved in teaching and research since 1996. Dr. Xing is a Cheung Kong Scholar and has published over 150 scientific refereed articles. His research work is ranked in the top 1# of cited authors for journals in environment and ecology. Dr. Xing received his PhD degree from the University of Alberta, Canada, in 1994. Pan Ming Huang, PhD, FAAAS, FASA, FCSSS, FSSSA, FWIF , is Professor Emeritus of Soil Science at the University of Saskatchewan in Saskatoon, Canada. Dr. Huang has published over 300 refereed articles and book chapters, written two books, edited eighteen others, and served on many editorial boards. He received the Distinguished Researcher Award from the University of Saskatchewan and the Soil Science Research Award from the Soil Science Society of America.