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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #350575
Research Project: Improving the Sustainability of Irrigated Farming Systems in Semi-Arid Regions

Location: Water Management and Systems Research

Title: Optimal water allocation under deficit irrigation in the context of Colorado water law

Author
item VARZI, MANIJEH - COLORADO STATE UNIVERSITY
item TROUT, THOMAS
item DeJonge, Kendall
item OAD, RAMCHAND - COLORADO STATE UNIVERSITY

Submitted to: Journal of Irrigation and Drainage Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2018
Publication Date: 2/20/2019
Citation: Varzi, M.M., Trout, T.J., DeJonge, K.C., Oad, R. 2019. Optimal water allocation under deficit irrigation in the context of Colorado water law. Journal of Irrigation and Drainage Engineering. 145(5). https://doi.org/10.1061/(ASCE)IR.1943-4774.0001374.
DOI: https://doi.org/10.1061/(ASCE)IR.1943-4774.0001374

Interpretive Summary: Deficit irrigation is one proposed method of conserving water without substantially decreasing farm profitability, by maximizing farm profit through optimizing water allocation between on-farm production and off-farm leases. This manuscript formulates optimal water allocation for a single farm using crop water production functions and the concept of deficit irrigation. According to the optimal allocation model used in this study, and with water leasing and maize and sunflower yield prices in Colorado during 2010-2016, deficit irrigation does not improve farm income. The model developed in this paper can define the crop and water leasing prices for which deficit irrigation is worthwhile.

Technical Abstract: Colorado’s growing urban areas often look to the agriculture sector as a source to satisfy their increasing water demand. The common belief is that in the agricultural sector there are opportunities to use less water and thus make saved water available to urban areas. Deficit irrigation is one proposed method of conserving water without substantially decreasing farm profitability. The key is for farmers to maximize farm profit through optimizing water allocation between on-farm production and off-farm leases. This manuscript formulates optimal water allocation for a single farm using crop water production functions and the concept of deficit irrigation. Using this model, optimal water allocation was determined based on maize and sunflower water productivity data collected during 2008-2011 growing seasons in eastern Colorado. According to the optimal allocation model, and with water leasing and yield prices during 2010-2016, deficit irrigation does not improve farm income. Although, in some years deficit irrigation could increase farm income, this improvement was minimal for maize. Sunflower had fewer opportunities to benefit from deficit irrigation, and when it did, most water was allocated to leasing, leaving only enough water to achieve minimal yield. The model developed in this paper can define the crop and water leasing prices for which deficit irrigation is worthwhile.