Soil Carbon Response to Projected Climate Change in the U.S. Western Corn Belt.

The U.S. Western Corn Belt is projected to experience changes in growing conditions due to climate change over the next 50 to 100 years. Projected changes include an increase in growing season length, an increase in the number of high temperature stress days and warm nights, and an increase in precipitation with more heavy rainfall events. The impact these changes will have on soil organic carbon (SOC) need to be estimated and adaptive changes in management developed to sustain soil health and system services. The process-based model CQESTR will be used to model changes in SOC stocks in continuous corn (Zea mays L.) and a corn-soybean [Glycine max (L.) Merr.] rotation under disk, chisel, ridge, and no-tillage using projected growing season conditions for the next 50 years. Input for the model will be based on management and harvest records from a long-term tillage study (1998 to 2011) in eastern Nebraska and model output will be validated using measured changes in SOC from that study. The validated model will be used to estimate changes in SOC over the next 50 years under projected changes in growing season temperature and precipitation. The effect of adding a mixed-species cover crop to this system will be included as one potential amelioration practice.