Relating United States crop land use to natural resources and climate change

Abstract

Crop yield response to climate change has been widely examined, but the sensitivity of crop land use to hypothetical climate change has not been examined directly. Crop land-use regression models for estimating crop area indices (CAIs) - the % of land used for corn, soybean, wheat, and sorghum production - are presented. Inputs to the models include available water-holding capacity of the soil, % of land available for rain-fed agricultural production, annual precipitation, and annual temperature. The total variance of CAI explained by the models ranged from 78% for wheat to 87% for sorghum, and the root-mean-square errors ranged from 1.74% for sorghum to 4.24% for corn. The introduction of additional climatic variables to the models did not significantly improve their performance. The crop land-use models were used to predict the CAI for every crop reporting district in the US for the current climatic condition and for possible future climate change scenarios. The magnitude of climatic warming suggested by GCMs (GISS and GFDL) is from 3.5° to 5.9°C for regions of the US. In general, small changes in temperature or precipitation produced larger corresponding changes (on a % basis) in soybean, wheat, and sorghum area than in corn area. -from Authors