Technologies for sustainable agriculture in the tropics : proceedings of two international symposia sponsored by Division A-6 of the American Society of Agronomy in San Antonio, TX, and Denver, CO, 1990 and 1991 respectively
editors, John Ragland and Rattan Lal ; organizing committee, John Ragland (1990), Augustine Uzo Mokwunye (1991) ; editorial committee, Kenneth Cassman ... [and others] ; editor[s] in chief, Gary A. Peterson, P.S. Baenziger, Robert J. Luxmoore