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ARS Home » Plains Area » Bushland, Texas » Conservation and Production Research Laboratory » Soil and Water Management Research » Research » Publications at this Location » Publication #401201
Research Project: Dryland and Irrigated Crop Management Under Limited Water Availability and Drought

Location: Soil and Water Management Research

Title: Center pivot water allocation strategies under limited irrigation

Author
item Schwartz, Robert
item DOMINGUEZ, ALFONSO - University Of Castilla-La Mancha(UCLM)
item PARDO, JOSE JESUS - University Of Castilla-La Mancha(UCLM)
item Klopp, Hans
item Baker, Trinity
item PARKER, DAVID - West Texas A & M University
item BELL, JOURDAN - Texas A&M Agrilife
item GUERRERO, BRIDGET - West Texas A & M University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/12/2023
Publication Date: 6/14/2023
Citation: Schwartz, R.C., Dominguez, A., Pardo, J., Klopp, H.W., Baker, T.J., Parker, D., Bell, J.M., Guerrero, B. 2023. Center pivot water allocation strategies under limited irrigation [abstract]. 2023 Universities Council on Water Resources (UCOWR)/National Institutes for Water Resources (NIWR) Annual Water Resources Conference, June 13-15, 2023, Fort Collins, Colorado. Session 34. Paper No. 4.

Interpretive Summary:

Technical Abstract: In the southern US Great Plains, groundwater for irrigation is declining because of aquifer depletion and reduced well yield. Under limited irrigation capacities, profitability for maize production can be optimized by allocating available water to a fraction of the pivot area. Irrigation can also be allocated to two crops with differing seasonal water requirements to optimize net returns. In this talk, we discuss the effects of reduced irrigation capacity on yield and allocation decisions for maize and cotton. Under limiting irrigation capacities, crop models must be linked to the spatiotemporal constraints of center pivot water applications to avoid overestimating application depths and simulated yields. Decreases in maize yield associated with limiting irrigation capacities is more pronounced in the Texas High Plains compared with western Kansas; oftentimes declining by more than 50% with a halving of irrigation capacity. Simulations using 25 years of weather data in Bushland, TX show that for a typical irrigation capacity of 7 mm d-1 (5.2 gpm ac-1), maximum profitability was achieved by irrigating 75% of the pivot area with the remaining area in fallow or dryland cotton. Concentrating water generated greater net returns because of lower seed and fertilizer costs and 25% greater corn yields that partially compensated for lack of production in fallow areas. Results of the first year of a study examining irrigation allocations within a field planted to an equal area of cotton and maize with a limiting irrigation capacity of 4.2 mm d-1 (3.1 gpm ac-1) demonstrated that concentrating irrigation on the maize until August resulted in $96 ac-1 greater net returns compared with a cotton solo crop. In addition, withholding 51 mm irrigation from maize prior to August and applying this amount to the cotton resulted in a 51% reduction in maize yield (p<0.001) and a 26% increase (p=0.047) in lint yield. Making informed water allocation decisions can permit producers to maintain profitability as groundwater irrigation becomes more limiting. Simulations and fields studies are jointly required to satisfactorily assess allocation decisions and trade-offs to develop decision aids for irrigators.