Assessing the impacts of long-term climate change on hydrology and yields of diversified crops in the Texas High Plains

Authors: WEN, NA - China Agricultural University; Marek, Gary; SRINIVASAN, RAGHAVAN - Texas A&M Agrilife; Brauer, David; QI, JUNYU - University Of Maryland; WANG, NAN - China Agricultural University; HAN, YIWEN - China Agricultural University; ZHANG, XUELIANG - China Agricultural University; FENG, PUYU - China Agricultural University; LIU, DE LI - Wagga Wagga Agricultural Institute; CHEN, YONG - China Agricultural University

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/30/2024
Publication Date: 8/5/2024
Citation: Wen, N., Marek, G.W., Srinivasan, R., Brauer, D.K., Qi, J., Wang, N., Han, Y., Zhang, X., Feng, P., Liu, D., Chen, Y. 2024. Assessing the impacts of long-term climate change on hydrology and yields of diversified crops in the Texas High Plains. Agricultural Water Management. 302. Article 108985. https://doi.org/10.1016/j.agwat.2024.108985.
DOI: https://doi.org/10.1016/j.agwat.2024.108985

Interpretive Summary: The impacts of climate change, including increased air temperatures and atmospheric CO2 concentrations, are expected to threaten global food security in both irrigated and rainfed crop production regions. Although the impacts of such increases are unknown, simulation modeling using global circulation models may provide insight into potential effects on crop production and soil and water resources. Researchers from USDA-ARS Bushland and university partners from the U.S., Australia, and China simulated the effects of climate change on hydrology and yields for staple crops in the Texas High Plains (THP) through the end of the of the 21st century. Simulations using a Soil and Water Assessment Tool (SWAT) model equipped with improved CO2 and autoirrigation algorithms suggested mixed changes in crop water use for irrigated crops and an overall increase for dryland crops. Simulated irrigation decreased overall with increases in yield for drought tolerant crops including cotton and sunflower. This study highlighted the efficacy of the improved SWAT model for evaluating alternative management strategies to reduce negative impacts of climate change.

Technical Abstract: Simulating the effects of future climate change on hydrology and crop yields provides opportunities for selecting appropriate crops and enhancing the climate change resilience of agricultural systems. The Texas High Plains, a major crop-producing region in the United States, faces significant challenges from climate change risks and dwindling groundwater supply from the Ogallala Aquifer. This study simulated the impacts of climate change on crop water requirements and yields of staple crops under both irrigated and dryland farming in addition to continuous fallow at Bushland of the Texas High Plains using an improved Soil & Water Assessment Tool (SWAT) model. The model incorporates management-allowed depletion (MAD) irrigation scheduling and a dynamic CO2 input method (SWAT-MAD-CO2). Future climate data projected by the latest bias-corrected 22 General Circulation Models (GCMs) of the Coupled Model Intercomparison Project 6 (CMIP6) under three Shared Socioeconomic Pathway (SSP) emission scenarios of SSP1-2.6 (SSP26), SSP2-4.5 (SSP45), and SSP5-8.5 (SSP85) were used. Modeled changes in actual evapotranspiration (ETa) varied across different irrigated crops as ETa generally increased (2.4-11.5percent) for dryland crops and continuous fallow under the future climate change scenarios compared to the baseline period (1986-2015). Irrigation water use (except irrigated cotton) was expected to decrease, with larger reductions under three SSP scenarios for future irrigated winter wheat (16.1-85.5 percent) and irrigated sorghum (18.1-78.0 percent) compared to other irrigated crops over two 30-year periods. Regarding crop yields, the annual yield for future irrigated cotton, irrigated sunflower, and dryland cotton was expected to increase by 109.3-142.7 percent, 1.1-9.4 percent, and 93.9-150.2 percent, respectively, compared to the baseline period. Conversely, the simulated yields of the irrigated sorghum and dryland soybean showed the greatest reductions of 6.4-27.3 percent and 5.9-51.3 percent, respectively, under the climate change scenarios relative to the baseline period.