Text this: International and national outlook--the necessity for efficient nutrient utilization : proceedings of a symposium / sponsored by Divisions S-4, S-8, A-4, and A-6 of the American Society of Agronomy and Soil Science Society of America ; coeditors, Noble R. Usherwood, Eugene C. Doll ; editor-in-chief, Matthias Stelly ; managing editor, David M. Kral ; assistant editor, Linda C. Eisele.