Soil-dependent responses of US crop yields to climate variability and depth to groundwater

The effects of climate variations on crop yield have been widely studied. However, the effects of soil on crop-climate responses are often ignored in crop yield prediction. We investigated the effects of soil texture and soil organic carbon concentration (SOC) on the yield responses of seven major crops (corn, winter wheat, soybean, cotton, barley, oats, rice) to growing season precipitation and temperature between 1958 and 2019 across the conterminous US. We also evaluated the effects of irrigation and groundwater depth on crop-climate responses. Crop yields were most sensitive to precipitation and temperature variability in coarse-textured soils and less responsive to these weather parameters in medium- and fine- textured soils. Increasing SOC concentration (> 2%) contributed to crop yields being less sensitive to precipitation – due to increased water retention, and less responsive to temperature – presumably due to increased buffering capacity against increased water lost through evapotranspiration. Irrigation and an intermediate depth to groundwater increase the resilience of crops to precipitation and temperature changes and these effects were also dependent on soil texture and SOC. To enhance food security for a rapidly growing global population under a changing climate, best management practices should be adopted that improve soil structure and carbon stocks that can increase soil available water storage (“Green Water”) and nutrient retention and promote energy conservation. The spatial-temporal variations of soil texture, SOC, and depth to groundwater should be considered in agricultural and ecosystem modeling to more accurately capture crop yield response to climate variations.