Andrew J. Margenot, Department of Crop Sciences, University of Illinois-Urbana-Champaign, Urbana, IL, US, Rolf Sommer, Soils Program, CIAT - Intl Center for Tropical Agriculture, Nairobi, Kenya, Nicolas A. Jelinski, Department of Soil, Water and Climate, University of Minnesota-Twin Cities, Saint Paul, MN, US, Sanjai J. Parikh, Department of Land, Air and Water Resources, University of California-Davis, Davis, CA and Louise E. Jackson, University of California-Davis, Davis, CA