Irrigation plays significantly different roles in influencing hydrological processes in two breadbasket regions

Authors: WANG, Y. - Iowa State University; ZHOU, Y. - Iowa State University; FRANZ, K.J. - Iowa State University; Zhang, Xuesong; QI, J. - University Of Maryland; JIA, G. - Chinese Academy Of Sciences; YANG, Y. - US Department Of Agriculture (USDA)

Submitted to: Science of the Total Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2022
Publication Date: 7/12/2022
Citation: Wang, Y., Zhou, Y., Franz, K., Zhang, X., Qi, J., Jia, G., Yang, Y. 2022. Irrigation plays significantly different roles in influencing hydrological processes in two breadbasket regions. Science of the Total Environment. 844:157253. https://doi.org/10.1016/j.scitotenv.2022.157253.
DOI: https://doi.org/10.1016/j.scitotenv.2022.157253

Interpretive Summary: Agricultural irrigation is the major cause of water shortages in numerous watersheds across the globe. Here, we applied the Soil and Water Assessment Tool (SWAT) model to quantify the influence of agricultural irrigation techniques on the water cycle in the Jing-Jin-Ji (JJJ) plain and northern Texas (NTX), where irrigation accounts for over 60% and 90% of total water use in the two regions, respectively. We found that, as compared to traditional irrigation practices, adopting the deficit irrigation technique can significantly reduce irrigation water use and surface runoff during the growing season. Our findings call for policies and regulations that can help farmers shift towards more efficient irrigation techniques in arid agricultural watersheds, particularly in the face of mounting water shortage challenges due to climate change and population growth

Technical Abstract: Agriculture is a major water user, especially in dry and drought-prone areas that rely on irrigation to support agricultural production. Irrigation accounts for more than 60% of water use in Jing-Jin-Ji (JJJ) and 90% in northern Texas (NTX). In recent years, these two regions have experienced increasing water demands due to climate change, population growth, and intensive agricultural irrigation. In this study, we estimated crop growth and irrigation water use during 2008 to 2013 in JJJ and NTX and explored the spatiotemporal variation of irrigation water use using the Soil and Water Assessment Tool (SWAT) model. The change of precipitation, irrigation techniques, and crop types significantly influenced the fluctuation of irrigation. Notably, the deficit irrigation technique has potential to reduce approximately 50% of irrigation water use in the southern JJJ and the western NTX, both of which include intensively irrigated cropland. Moreover, surface runoff in these two regions could increase by approximately 50% during the growing season. Our findings highlight the substantial impacts of irrigation on the water cycle in the two droughty breadbasket regions in the US and China, and herald the mounting water shortage challenges in these regions for providing food under growing population and changing climate. The great potential to reduce groundwater extraction by adopting water conservation irrigation techniques calls for policies and regulations that can help farmers shift towards more sustainable water management practices.