Advisor Board

Advisory Board Martin Alexander

Eugene J. Kamprath

Cornell University

North Carolina State University

Kenneth J. Frey

Larry P. Wilding

Iowa State University

Texas A& M University

Prepared in cooperation with the

American Society of Agronomy Monographs Committee M. A. Tabatabai, Chairman S. H. Anderson D. M. Kral P. S. Baenziger S. E. Lingle W. T. Frankenberger, Jr. R. J. Luxmoore

G. A. Peterson S. R. Yates