Are U.S. Corn and Soybeans Becoming More Drought Tolerant?
Abstract
The hypothesis that corn and soybeans have become more drought tolerant is tested by regressing county yields on a drought index and time. Results indicate that corn yield losses from drought of a given severity, whether measured in quantity terms or as a percentage of mean yields, have decreased over time. Soybean percentage yield losses have also declined, but absolute losses have remained largely constant. The potential impact of increased drought tolerance on U.S. crop insurance rates is illustrated by comparing Group Risk Plan premium rates assuming time-invariant susceptibility to drought with rates generated from this article’s regression results.