Assessment of alternative agricultural land use options for extending the availability of the Ogallala Aquifer in the Northern High Plains of Texas

Authors: CHEN, YONG - Texas A&M University; Marek, Gary; MAREK, THOMAS - Texas A&M Agrilife; Moorhead, Jerry; HEFLIN, KEVIN - Texas A&M Agrilife; Brauer, David; Gowda, Prasanna; SRINIVASAN, RAGHAVAN - Texas A&M University

Submitted to: Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2018
Publication Date: 9/26/2018
Citation: Chen, Y., Marek, G.W., Marek, T.H., Moorhead, J.E., Heflin, K.R., Brauer, D.K., Gowda, P.H., Srinivasan, R. 2018. Assessment of alternative agricultural land use options for extending the availability of the Ogallala Aquifer in the Northern High Plains of Texas. Hydrology. 5(4):53. https://doi.org/10.3390/hydrology5040053.
DOI: https://doi.org/10.3390/hydrology5040053

Interpretive Summary: Decreased irrigation well capacities due to declining groundwater levels in the Ogallala Aquifer will eventually limit the production of corn in the Northern High Plains of Texas, one of the region’s most profitable crops. Alternatively, less water intensive crops may conserve groundwater while allowing producers to remain profitable. Therefore scientists from ARS in Bushland TX and Texas A&M AgriLife Research and Extension Service used Soil and Water Assessment Tool (SWAT), equipped with a newly developed irrigation program to simulate water use associated with alternative crops including soybean, sunflower and grain sorghum. Results indicated irrigation amounts were reduced by 19, 21, and 32% respectively, as compared to corn. These results are of interest to farmers, crop consultants and regional water policy makers.

Technical Abstract: The Ogallala Aquifer has experienced a continuous decline in water levels due to decades of irrigation pumping with minimal recharge. Corn (Zea mays L.) is one of the major irrigated crops in the semi-arid Northern High Plains (NHP) of Texas. Selection of less water-intensive crops may provide opportunities for groundwater conservation and viable production options for producers with limited well capacities. Modeling the long-term hydrologic impacts of alternative crops can be a time-saving and cost-effective alternative to field-based experiments. A newly developed management allowed depletion (MAD) auto-irrigation algorithm for Soil and Water Assessment Tool (SWAT) allows for simulation of prevailing irrigation management practices used in the NHP. Results indicated that simulated irrigation, evapotranspiration, and crop yield were representative of the measured field data. Approximately 19%, 21%, and 32% reductions in groundwater use were associated with irrigated soybean, sunflower, and grain sorghum, respectively, as compared to irrigated grain corn. On average, soil water depletion was more than 52 mm of the dryland farming scenarios. In contrast, only 18 mm of soil water was lost to evaporation for a long-term entire-year fallow simulation. The fallow scenario also showed 31 mm of water percolating below the root zone with the potential for aquifer recharge.