Weather Effects on Crop Yield Distribution
The estimated parameters of the expected yield equations for corn, soybean, and winter wheat are listed in Table 1. The Chi-square statistics are statistically significant implying that the climatic variables are jointly able to explain the expected yield values. The most important weather variable across all three crops is length of the growing season. A 10% increase in the number of growing days is estimated to increase yield by approximately 5% for all three crops. It is the length rather than the intensity of the season that influences crop yield because the average temperature has a marginal and generally insignificant effect. The other climatic variables that are important across all crops are the variation in temperature and precipitation. As expected, increases in the deviation of these climatic