Are U.S. Corn and Soybeans Becoming More Drought Tolerant?
通过将县级产量与干旱指数和时间进行回归，检验了玉米和大豆耐旱性增强的假设，发现玉米的干旱损失随时间减少，大豆的百分比损失也下降，但绝对损失基本不变，并展示了耐旱性增强对作物保险费率的影响。
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.