FIG. 49.17 Corn yield and area in the United States and globally from 1961 to 2007. Global corn yield and area have increased at about the same rate, whereas U.S. corn yield has risen much more quickly than corn area because of energy-intensive agriculture and use of fertilizer. Source: Data from M. D. Edgerton, 2009, “Increasing Crop Productivity to Meet Global Needs for Feed, Food, and Fuel,” Plant Physiology 149:9, http://www.plantphysiol.org/content/149/1/7.