Location: Water Management and Systems ResearchTitle: An Economic and Biophysical Model of Deficit Irrigation
|MANNING, DALE - Colorado State University|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2019
Publication Date: 11/1/2019
Citation: Trout, T.J., Manning, D. 2019. An Economic and Biophysical Model of Deficit Irrigation. Agronomy Journal. 111(6):3182-3193. https://doi.org/10.2134/agronj2019.03.0209.
Interpretive Summary: Irrigation farmers in the western U.S. normally attempt to fully irrigate their crops to maximize yield and gross income. Due to high water costs and limited water supplies, deficit irrigation may be a better economic option. With deficit irrigation, irrigation is reduced, costs are reduced, and yields are reduced. In some areas of the west, water markets create an opportunity for farmers to lease a portion of their water, such that water becomes one of their sources of income. A model is presented that can assist farmers determine whether deficit irrigation with water leasing will increase their net income. Because the marginal value of water often decreases near full irrigation, deficit irrigation with leasing will often provide the highest farm income.
Technical Abstract: High water cost may make deficit irrigation economically viable, especially when water can be leased to other users. Deficit irrigation decisions depend on market prices, costs of production, and biophysical conditions that a producer faces. The mechanisms through which these factors jointly influence optimal irrigation strategies are complex. Although deficit irrigation will reduce crop yield, it may increase farmer net income and sustainability of the farming enterprise. We develop a model that describes how economic and biophysical factors jointly contribute to net income in irrigated crop production. A model application of irrigated maize production in northeast Colorado illustrates the conditions under which deficit irrigation increases net income. High water cost and low crop price favor deficit irrigation. When water has value for leasing, the combination of production under deficit irrigation and water leasing may increase net income. High lease price and low commodity price may favor rainfed production or fallowing.