Impact of Timing, Severity, and Duration of Drought on Crop Yield in the United States

Drought is one of the most damaging climatic stressors for crop production and could cause huge economic losses. Since 1980, drought events in the United States have increased significantly, and their frequency, duration, and severity are expected to continue to increase in the future, which pose huge threats to future food security. However, the impact of timing, severity, and duration of drought on crop yields is still unclear, which greatly hinders our progress in making adaptive strategies to reduce drought risk to crop production. In this study, we used an improved agricultural ecosystem model (Dynamic Land Ecosystem Model (DLEM)-AG2.0) to estimate yield of three major crops (i.e., corn, soybean, and winter wheat) in the United States during the period of 1964-2018. We also quantified yield loss caused by drought and examined crop yield response to the timing, severity, and duration of drought through combining the Standardized Precipitation Evaporation Index. Simulation results indicate that DLEM-AG2.0 is capable of accurately reproducing the spatial pattern and temporal trends of yield of corn, soybean, and winter wheat, and well capturing drought-induced crop yield loss. In addition, we found that crop yields show high sensitivity to the timing, severity, and duration of drought, and there are also differences between the yields of different crops in response to drought. Our study highlights the need to develop adaptive strategies to mitigate the negative impact of extreme climate events on food security.