As global warming intensifies, rising temperatures and droughts are posing increasingly severe challenges to food production. Irrigation is one of the most critical method for agriculture to cope with climate change, effectively mitigating yield losses caused by heat and drought. However, agriculture is also a major consumer of water resources, and indiscriminate expansion of irrigated areas could further exacerbate water scarcity. Under the background, how should limited water resources and farmland water conservancy investment be allocated? Should existing farmland be fully upgraded to the most efficient water-saving irrigation systems, or should irrigated areas be moderately expanded? Should different crops and regions adopt differentiated investment strategies?

Recently, a research team led by Dr. ZHANG Tianyi from the Institute of Atmospheric Physics Chinese Academy of Sciences, in collaboration with researchers from Hohai University, Xiamen University, Peking University, Renmin University of China, China Agricultural University, the University of Maryland, and Yale University, published a paper online entitled "Coupling irrigation technology upgrades with targeted expansion enables water-efficient and climate-resilient cereal production in China " in Nature Food. The study integrates 42,190 county-level agricultural statistical records, 3,576 household socioeconomic survey responses, and 2,230 irrigation technology comparison trials. Focusing on China's three staple crops (maize, wheat, and rice) the research systematically evaluates the development trends of various water-saving irrigation technologies and incorporates both technology upgrades and expansion of irrigated areas into an investment optimization framework, proposing differentiated irrigation investment pathways that balance water conservation, food security, and return on investment.

Significant irrigation technology transition, but with notable regional disparities

Household survey data show that China's agricultural irrigation has undergone a marked technological transition over the past decade. In 2010, earthen-channel water delivery and flood irrigation were still widespread; by 2022, these inefficient practices had declined substantially, while the adoption of various water-saving technologies continued to rise. However, the pace of technological transition varies significantly across different crops and regions.

Professor WANG Jinxia of Hohai University said that "Upgrading irrigation and water-saving technologies has always been a key component of China's farmland water conservancy investment. This study used large-scale household survey data to quantitatively assess different irrigation technologies by crop and by region. At the current rate of technology adoption, irrigation water use per area for the three staple crops is projected to decrease by only 9.4%–16.0% by 2030, falling notably short of the 25.5% water-saving target set by the National Plan for Sustainable Agricultural Development (2015–2030)." (Note: The Plan stipulates that national agricultural irrigation water use should be capped at 373 km3 by 2030, representing a 25.5% reduction compared to the 2010s.)

Technology upgrades alone cannot offset climate change impacts

In further analyzing future trends, the research team found that while deploying the most efficient irrigation technologies across all existing irrigated areas could more than meet water-saving targets, the negative impact of future climate change on crop yields remains substantial. The yield gains from irrigation technology upgrades alone would be insufficient to offset the potential production losses caused by climate change, thereby threatening China's food security.

Improve efficiency first then expand, tailored by crop and region

Based on these findings, the research team proposed a new approach: first improve water-use efficiency on existing irrigated areas, and then, within the limits of water resource constraints, redirect the "water savings" to convert portions of rainfed farmland to irrigated agriculture, as a strategic resource allocation scenario to address the adverse effects of future climate change.

Further investment portfolio analysis reveals differentiated optimal strategies by crop: for maize, adopting more advanced irrigation technologies while moderately expanding irrigated area is the preferred option; for wheat and rice, the demand for additional irrigated area is relatively modest, and deploying medium-efficiency water-saving irrigation technologies on newly-developed irrigated area is sufficient to ensure food security under future climate conditions, meet water-saving policy targets, and maximize investment returns.

"The real question policymakers need to answer is: which crops need irrigation, where should irrigated area be expanded, by how much, what technologies should be adopted, and whether the investments are economically viable," said Dr. ZHANG Tianyi. "Previous studies have largely focused on projecting future changes in irrigated area, but have struggled to simultaneously capture the interplay between irrigation technologies and the relationship between existing and newly-developed irrigated areas. By integrating multi-source data and developing a new analytical framework, this study aims to provide more actionable scientific evidence for these specific investment decisions."

Irrigation is not the only solution

The research team also emphasized that irrigation is not the sole means of addressing future climate change and safeguarding food security. Agricultural production is also influenced by crop variety breeding, cultivation management, land management scale, and other factors. Therefore, irrigation investment should be coordinated with the development of stress-tolerant crop varieties, climate-resilient cultivation practices, and the construction of high-standard farmland.

Dr. CHEN Huang of Xiamen University stated, "The three independent data sources used in this study come from different survey and research pathways, yet the model is able to effectively capture the decline in agricultural irrigation water use and the improvement in irrigation productivity in China over the past decade. Future research will further incorporate agricultural policy and economic factors such as farmland consolidation and changes in agricultural commodity prices, to refine the comprehensive assessment of irrigation investment."

The first author of the paper is Dr. ZHANG Tianyi from the Institute of Atmospheric Physics, CAS. The corresponding authors are Dr. ZHANG Tianyi, Professor WANG Jinxia of Hohai University, and Dr. CHEN Huang of Xiamen University. Co-authors include Professor ZHOU Feng of Peking University, Academician KANG Shaozhong of China Agricultural University, Dr. JIN Zhelong of Peking University, PhD candidate LIU Yuting of Renmin University of China, and PhD candidate CHAO Wei of Peking University, as well as Professor Weston Anderson of the University of Maryland and Professor Robert O. Mendelsohn of Yale University.

This research was supported by the National Key R&D Program of China (2024YFF0808402), the National Natural Science Foundation of China (42575205; 72394401), the Earth System Numerical Simulation Facility of CAS, and the CGIAR Initiative on Climate Resilience (ClimBeR).

Paper info:

Zhang, T., Wang, J., Chen, H., Liu, Y., Chao, W., Zhou, F., Kang, S., Jin, Z., Anderson, W., Mendelsohn, R.O. 2026. Coupling irrigation technology upgrades with targeted expansion enables water-efficient and climate-resilient cereal production in China. Nature Food. https://doi.org/10.1038/s43016-026-01455-5.

This conceptual graphical abstract illustrates that optimizing both irrigation technology upgrades and expansion is crucial to achieving multiple targets: water conservation, agricultural climate resilience, and long-term investment return. This study conducts an investment portfolio analysis to accelerate the government’s progress toward SDGs within irrigation infrastructure and high-standard farmland construction plans. Image by ZHANG Tianyi and Wang Jinxia