Local effects of climate change on row crop production and irrigation adoption

Abstract

Global climate change will affect crop productivity, technology adoption, and commodity food and fiber prices. This research investigates the ex-ante effects of climate change on cropping mix and irrigation decisions at a watershed scale by integrating a downscaled General Circulation Model (GCM) projections, a crop growth model, and an economic model of the row crop sector typical of corn, soybean, wheat, and sorghum operations in Tennessee, United States. The downscaled GCM is used to generate weather patterns for Tennessee’s watersheds to 2049, under moderate and high greenhouse gas (GHG) emission assumptions. Crop yields and commodity prices were also estimated under these prevailing climate scenarios. Compared with the moderate emission level scenario, greater GHG emissions decrease dryland crop productivity and cause commodity prices to trend upward. A row crop optimization model was developed under the assumption that producers are profit maximizers who base their cropping decisions on the previous yield performance of a cropping system, commodity prices, and production functions, subject to resource constrains. Results suggest that producers in some watersheds adopt irrigation to minimize variability in net returns if water is available. Dryland and irrigated soybeans, dryland corn, and dryland soybean-wheat double cropping could become the dominant cropping systems in watersheds located in western Tennessee while irrigated and dryland soybeans could become the dominant row crop in watersheds located in middle Tennessee.