Professor, Soil Ecology, Colorado State University

Visiting Scholar, Stanford and Scientist Emeritus, USGS

School of Agriculture & Environment; UWA Institute of Agriculture, University of Western

Principal Scientist-Soil Systems Modeler, International Fertilizer Development Center

Professor of Plant Pathology, Emerging Pathogens Institute, University of Florida

Research Director, A&L Biologicals, Canada

Research Soil Scientist, USDA< Agricultural Research Service, Retired

Soil Scientist (Microbiologist/Biochemist), USDA-ARS

Professor, Cornell University

Professor of Agronomy, Purdue University