Climatic Change, Weather Variability, and Corn Production1

Abstract

AbstractA crop/weather model was used to determine the impact of changes in climate and weather variability on corn (Zea mays L.) production from 1891 to 1983. Five Corn Belt states, Illinois, Indiana, Iowa, Missouri, and Ohio, were included in the study. These states produce over 50% of the U.S. corn crop. A cooling trend from 1930 to 1972 was accompanied by increasing rainfall in July and August, and by decreasing weather variability. These three factors were favorable for corn yield increase. Simulated corn yields, calculated from weather data, increased 970 kg ha−1 from 1930 to 1972 because of improved weather for corn. After 1972 there was greater weather variability and higher intensity rainfall events. Fertilizer use on corn increased substantially in the 1960s and increased at slower rate after 1972. The annual increase in corn yield with normal weather after 1972 was less than half as much as it was from 1960 to 1972. Highest yields of corn have been associated with normal preseason precipitation, normal June temperature, below normal temperature in July and August, and above normal rainfall in July and August. The period after 1970 was expected to warm but weather variability has masked the identification of a trend.