Contributors

Iowa MSEA
ISU
Carl Anderson Agricultural & Biosystems Engineering James L. Baker Agricultural and Biosystems Engineering Fred Blackmer Agronomy Joel Coats Entomology Richard Cruse Agronomy William Crumpton Botany Jerald DeWitt Entomology	Mike Duffy Agriculture Economics Ramesh Kanwar Agricultural and Biosystems Engineering Gerald Miller Agronomy Steve Oberle Extension Specialist Steve Padgitt Sociology Margaret Smith Extension Specialist W.W. Simpkins Geological and Atmospheric Sciences
USDA/ARS National Soil Tilth Laboratory
Mike R. Burkart Cynthia A. Cambardella Dana L. Dinnes Jerry L. Hatfield Dan B. Jaynes Tom B. Moorman	Amy .J. Morrow Tim B. Parkin Richard L. Pfeiffer John H. Prueger T. R. Steinheimer