Managing Weather Risk for Cotton in Texas High Plains with Optimal Temporal Allocation of Irrigation Water

Texas High Plains (THP) is a major cotton producing region in the US with low rainfall and decreasing irrigation water availability. Hence stochastic rainfall poses considerable production risk in the region and developing strategies to maximize the average profit and minimize the year to year variability in profits is an important concern. In this study, Cotton2K, which is a process based cotton growth simulation model, was used along with an economic optimization model to identify the optimal strategies for temporal allocation of irrigation water for center pivot irrigated cotton in THP. The study analyzed different strategies to allocate irrigation water during one growing season among three different growth stages of cotton (planting to first bloom, first bloom to first open boll, and first open ball to 60% open boll) at four different sub-optimal levels for irrigation water availability (6, 9, 12, and 15 acre-inches). The results showed that the profit and utility maximizing strategy was to apply all available irrigation water during stage II when six, nine, and twelve acre-inches of irrigation water were available. When fifteen inches of irrigation water was available, the optimal strategy was to use 90% of the available irrigation water in stage II and the rest in stage III. The sensitivity analysis indicated that these optimal decisions were not sensitive to variations in price of cotton lint and farmer’s attitude towards risk.