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.

全球气候变化将影响作物的生产力，技术采用以及商品食品和纤维价格。这项研究调查了事前气候变化对流域尺度上的种植混合和灌溉决策的影响，方法是将缩小的通用循环模型（GCM）预测，作物生长模型以及典型的玉米，大豆，小麦和高粱的行作物经济模型整合在一起在美国田纳西州运营。在中高温室气体（GHG）排放假设下，缩小的GCM可用于生成田纳西州流域到2049年的天气模式。在这些普遍的气候情景下，还估计了作物单产和商品价格。与中等排放水平的情景相比，温室气体排放量增加会降低旱地作物的生产力，并导致商品价格上涨。在假定生产者是利润最大化者的前提下，开发了行间作物优化模型，他们的作物决策基于作物系统以前的产量表现，商品价格和生产功能而受到资源的限制。结果表明，如果有水，某些流域的生产者会采用灌溉措施以最大程度减少净收益的波动。在田纳西州西部流域，旱地和灌溉大豆，旱地玉米和旱地大豆/小麦双重作物可能成为主要的种植系统，而田纳西州中部的流域，灌溉和旱地大豆可能成为主要的行作物。结果表明，如果有水，某些流域的生产者会采用灌溉措施以最大程度减少净收益的波动。在田纳西州西部流域，旱地和灌溉大豆，旱地玉米和旱地大豆/小麦双重作物可能成为主要的种植系统，而田纳西州中部的流域，灌溉和旱地大豆可能成为主要的行作物。结果表明，如果有水，某些流域的生产者会采用灌溉措施以最大程度减少净收益的波动。在田纳西州西部流域，旱地和灌溉大豆，旱地玉米和旱地大豆/小麦双重作物可能成为主要的种植系统，而田纳西州中部的流域，灌溉和旱地大豆可能成为主要的行作物。