Abstract
An investigation was made of variations in corn and soybean yields resulting from natural fluctuations in weather conditions between years in a five-state area in the Midwest. Analyses were performed for crop districts within each state and for various combinations of the five states when crop yields are evaluated over periods of 1-5 years. Results were presented in the form of temporal-spatial probability distributions, in which the distributions were based on deviations from “expected” yield after adjustment for technology advancements during the period of record (1931-75). In general, it was found that weather-related deviations in corn yield were greater than in soybeans, a decrease in temporal variability occurs from west to east, negative deviations tend to be greater than positive deviations, but that the five-state area seldom experiences large deviations from expected yield and the occasional large deviations do not usually persist long.
