Matt Liebman is a Professor of Agronomy and the Henry A. Wallace Endowed Chair for Sustainable Agriculture at Iowa State University. He received a B.A. in biological sciences from Harvard University and a Ph.D. in botany from the University of California-Berkeley. Matt was one of the founding members of ISU's Graduate Program in Sustainable Agriculture and served as that program's chair from 2004 through 2007, and held the Pioneer Agronomy Professorship from 2001 through 2004. Matt teaches a graduate course on ecologically based pest management strategies, and was a co-author of the book Ecological Management of Agricultural Weeds, published in 2001 by Cambridge University Press. Currently, he is a member of a research team investigating the productivity and environmental impacts of contrasting biofuel production systems, ranging from perennial prairie species to no-till corn. More details about his interests, responsibilities, and activities are available at http://www.wallacechair.iastate.edu.

Johannes Lehmann, an associate professor of soil fertility management and soil biogeochemistry, joined the faculty at Cornell University in 2001. Prior to his appointment at Cornell, he coordinated an interdisciplinary research project on nutrient and carbon management in the central Amazon for the Federal Research Institution of Forestry, and the University of Bayreuth, Germany. His work experience includes applied and basic research in Sudan, Togo, Tanzania, Kenya, Malawi, Brazil, Colombia and Ecuador. Professor Lehmann's publications range from dryland research and nutrient cycling in irrigation systems to the rehabilitation of highly weathered soils in the humid tropics, from research on phosphorus dynamics in heavily manured soils to basic principles of carbon cycling in soils.