Maximizing profits via irrigation timing for capacity-constrained cotton production

Authors: MITCHELL-MCCALLISTER, DONNA - Texas Tech University; WILLIAMS, RYAN - Texas Tech University; BORDOVSKY, JAMES - Texas A&M Agrilife; MUSTIAN, JOSEPH - Texas A&M Agrilife; RITCHIE, GLEN - Texas Tech University; LEWIS, KATIE - Texas A&M Agrilife

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/2019
Publication Date: 12/6/2019
Citation: Mitchell-McCallister, D., Williams, R., Bordovsky, J., Mustian, J., Ritchie, G., Lewis, K. 2019. Maximizing profits via irrigation timing for capacity-constrained cotton production. Agricultural Water Management. 229. Article 105932. https://doi.org/10.1016/j.agwat.2019.105932.
DOI: https://doi.org/10.1016/j.agwat.2019.105932

Interpretive Summary: Cotton farmers on the High Plains of Texas face reduced irrigation capacities as the Ogallala Aquifer decline. By determining the optimal timing of irrigation, producers may be able to conserve irrigation water and reduce their pumping expenses. However, data regarding the optimum time and amount for applications are lacking. Working in a project funded by the USDA ARS Ogallala Aquifer Program, scientists from Texas Tech University and Texas A&M AgriLife compared cotton lint yields and profitability as affected by irrigation capacity and timing of irrigation deficit in one of three growth stages using a LEPA center pivot irrigation system on Pullman Clay/Olton soils. On average, treatments without irrigation in the early growth stages capacity made 6% less yield but saved 30% more water and generated the same profitability compared with irrigating in all three growing stages with an irrigation capacity of 2.25 gallons per min per acre. These results indicate that the profitability of cotton production can be maintained while applying little or no irrigation water early in the growing season.

Technical Abstract: Cotton producers on the southern High Plains of Texas face reduced seasonal irrigation capacities as groundwater resources from the Ogallala Aquifer decline. Technological advancements have allowed producers to achieve maximal water use efficiencies (>95 %); however, new management strategies are necessary to sustain producer profitability. By determining the optimal timing of irrigation, producers may be able to conserve irrigation water and reduce their pumping expenses. In a field experiment conducted from 2010 to 2013, cotton (Gossypium hirsutum L.) lint yield and profitability were compared across 27 irrigation treatments using a LEPA irrigation system on Pullman Clay/Olton soils. Irrigation was applied during three growing periods determined by growing degree days (GDD15.6), where P1=emergence to 525 GDD15.6, P2'='525–750 GDD15.6, and P3'>'750 GDD15.6. Treatments for the experiment included three irrigation capacities of 0, 3.2, and 6.4'mm d-1 in a randomized block design with three replications. Profitability was assessed by calculating gross margin from economic budgets that included the management operations from each year. On average, treatments with an irrigation capacity of 0'mm d-1 in P1 made 6 % less yield but saved 30 % more water and generated the same profitability as the IC treatments of 3.2'mm d-1. Irrigation during P3 at the 6.4'mm d-1 irrigation capacity (IC) was the most critical for yield potential, generating 114 % more yield than the 0'mm d-1 IC and 27 % more than the 3.2'mm d-1 IC treatments, resulting in a 468 % and 110 % increase in profit, respectively.