China News Service, Beijing, November 2 (Reporter Sun Zifa) As global warming intensifies, high temperatures and drought are posing increasingly severe challenges to food production. Irrigation is one of the most critical means for agriculture to cope with climate change. In this context, how investment in irrigation water conservancy should balance water conservation and food security has attracted much attention.
The reporter learned from the Institute of Atmospheric Physics of the Chinese Academy of Sciences on November 2 that researcher Zhang Tianyi from the institute recently teamed up with Chinese and foreign collaborators to study and propose the optimal Chinese path for differentiated irrigation investment that takes into account agricultural water conservation, food security, and investment returns based on relevant data and comparative experiments on China's three major staple food crops of corn, wheat, and rice.
Focus on three major staple crops
This important research result on food security under the background of climate change was completed by the Institute of Atmospheric Physics of the Chinese Academy of Sciences, Hohai University, Xiamen University, Peking University, Renmin University of China, China Agricultural University, and the University of Maryland and Yale University in the United States. The related paper is titled "Combining irrigation technology upgrades with targeted expansion to achieve water-saving and climate-resilient grain production in China." It was recently published online in the international professional academic journal "Nature Food".
Researcher Zhang Tianyi, the first author and co-corresponding author of the paper, introduced that this study integrated 42,190 county-level agricultural statistical data, 3,576 farmers' socioeconomic survey data, and 2,230 irrigation technology comparative experiments, focusing on China's three major staple food crops of corn, wheat, and rice. Based on a systematic evaluation of the development trends of different irrigation water-saving technologies, technology upgrades and new irrigation areas were incorporated into a unified investment optimization framework, and a differentiated irrigation investment path was proposed that takes into account agricultural water conservation, food security, and investment returns.
Farmer survey data shows that China's agricultural irrigation has undergone a technological transformation in the past ten years. In 2010, earthen canal water delivery and flood irrigation were still very common; by 2022, these inefficient irrigation methods had been significantly reduced, and the proportion of use of various water-saving technologies continued to rise. However, the technological transformation process differed significantly between different crops and different regions.
Research proposes new ideas
Professor Wang Jinxia of Hohai University, co-corresponding author of the paper, pointed out that the upgrading of irrigation water-saving technology has always been an important part of China's farmland water conservancy investment. This study used large-scale farmer household survey data to conduct a quantitative assessment of different irrigation technologies by crop and region. According to the update rate of existing irrigation water-saving technologies, the average irrigation water consumption per mu of the three major staple food crops is expected to be reduced by only 9.4%-16.0% by 2030, which is still significantly different from the 25.5% water-saving target proposed in the National Agricultural Sustainable Development Plan (2015-2030).
When analyzing future trends, the research team found that although fully deploying the most efficient irrigation technology on the existing irrigation area can exceed the water-saving target, future climate change will have a significant negative impact on crop yields. It is difficult to offset the potential yield losses caused by climate change by relying solely on the effects of irrigation technology upgrades, which will affect China's food security.
Based on this, the research team proposed a new idea: first improve water use efficiency in the existing irrigation area, and then use the saved "water resources space" for the irrigation transformation of some rain-fed farmland within the scope of water resource constraints to cope with the negative impact of future climate change as a resource allocation plan at the planning level.
Further investment portfolio analysis shows that in terms of new irrigated area, corn is suitable for adopting more advanced irrigation technology and moderately expanding the irrigated area; wheat and rice have relatively small demands for new irrigated area. Using medium-efficiency water-saving irrigation technology on the new irrigated area can achieve water-saving policy goals and maximize investment returns while ensuring food security under future climate change.
Collaboration is still needed in the future
"The questions that policymakers really need to answer are: which crops need to be irrigated, which areas should add irrigated area, how much, what technology should be used, and what the economic feasibility is." Zhang Tianyi believes that past research has often focused on future changes in irrigated area, but it is difficult to accurately characterize irrigation technology and the difference between existing and newly added irrigated area. By integrating multi-source data and constructing a new analysis framework, this study hopes to provide a more actionable scientific basis for these specific investment decisions.
The research team also emphasized that irrigation is not the only means to cope with future climate change and ensure food security. Agricultural production is also affected by many factors such as variety selection, cultivation management, and land management scale. Therefore, in the future, it is still necessary to coordinate irrigation investment with stress-resistant variety selection, climate-resilient cultivation management, and high-standard farmland construction and other measures.
Dr. Chen Huang, co-corresponding author of the paper and Xiamen University, said that the three independent data sources used in this study came from different disciplines and research paths, and the model can better reflect the evolution of China's agricultural irrigation water decline and irrigation productivity improvement over the past decade. Future research will further incorporate agricultural policy and economic factors such as farmland scale and changes in agricultural product prices to further improve the comprehensive assessment of agricultural irrigation investment.
