Impact of High Crop Prices on Environmental Quality: A Case of Iowa and the Conservation Reserve Program
研究玉米价格上涨如何导致爱荷华州保护储备计划中的环境敏感土地重新被开垦，并估算由此带来的土壤侵蚀、养分流失和碳封存损失，对政策制定者评估农业补贴与环境保护的权衡有参考价值。
Growing demand for corn due to the expansion of ethanol has increased concerns that environmentally sensitive lands retired from agricultural production into the Conservation Reserve Program (CRP) will be cropped again. Iowa produces more ethanol than any other state in the United States, and it also produces the most corn. Thus, an examination of the impacts of higher crop prices on CRP land in Iowa can give insight into what we might expect nationally in the years ahead if crop prices remain high. We construct CRP land supply curves for various corn prices and then estimate the environmental impacts of cropping CRP land through the Environmental Policy Integrated Climate (EPIC) model. EPIC provides edge-of-field estimates of soil erosion, nutrient loss, and carbon sequestration. We find that incremental impacts increase dramatically as higher corn prices bring into production more and more environmentally fragile land. Maintaining current levels of environmental quality will require substantially higher spending levels. Even allowing for the cost savings that would accrue as CRP land leaves the program, a change in targeting strategies will likely be required to ensure that the most sensitive land does not leave the program.