ECSENOMICS Diminishing returns in Corn Production 1-50 Figure 6-2 150 200 300 Phosphorus fertilizer input (pounds per acre) McGraw-Hilllrwin Source: Earl O. Heady, John T. Pesek, and william G. Brown, Crop Response Surfaces and Economic Optima in Fertilizer Use Agricultural Experiment Station, lowa State College, Ames, IA 1955), Table A-15.McGraw-Hill/Irwin Copyright © 2001 The McGraw-Hill Companies, Inc. All rights reserved. Diminishing Returns in Corn Production T-50 Figure 6-2 Source: Earl O. Heady, John T. Pesek, and William G. Brown, Crop Response Surfaces and Economic Optima in Fertilizer Use (Agricultural Experiment Station, Iowa State College, Ames, IA 1955), Table A-15