BEIJING, Oct. 27 (Xinhua) -- A new study shows that China may better balance water conservation, food security and investment returns by adopting more efficient irrigation strategies, and expanding irrigated farmland only where conditions are optimal.
The study, published in the journal Nature Food, was led by researchers at the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences, Hohai University and Xiamen University, in collaboration with several other Chinese and international institutions.
As rising temperatures and droughts put more pressure on food production systems, irrigation is becoming more important for farmers adapting to climate change. But expanding irrigated farmland further burdens already limited water supplies. The researchers therefore look for ways to save water, protect cereal production and improve investment returns all at once.
The team examined 42,190 county-level agricultural statistical records, 3,576 household socioeconomic survey responses and 2,230 irrigation technology comparison trials. It also focused on China's three staple crops: maize, wheat and rice.
The study found that China's agricultural irrigation underwent a significant technological transition between 2010 and 2022. In 2010, earthen-channel water delivery and flood irrigation were still widespread. By 2022, these inefficient practices had declined substantially, while water-saving technologies had become more common. However, the pace of change varied widely across crops and regions.
Wang Jinxia, a professor at Hohai University in east China's Jiangsu Province, said upgrading irrigation and water-saving technologies has long been a key part of China's farmland water conservancy investment.
Wang explained that at the current rate of technology adoption, irrigation water use per area for the three staple crops is projected to fall by only 9.4 percent to 16 percent by 2030. This projected reduction would fall short of the 25.5 percent water-saving target set by the national agricultural sustainable development plan for 2015 to 2030. The plan sets a cap of 373 cubic kilometers on national agricultural irrigation water use by 2030.
The study showed that deploying the most efficient irrigation technologies across all existing irrigated areas could more than meet the water-saving target. However, even such widespread upgrades would not be enough to offset possible crop yield losses caused by future climate change, posing risks to food security.
The researchers therefore proposed a new approach: first improve water-use efficiency in existing irrigated areas, and then, within water resource constraints, use the water saved to convert some rainfed farmland into irrigated farmland. The strategy aims to reduce the adverse effects of future climate change.
The study also found different optimal strategies for the three crops. For maize, the preferred approach is to adopt more advanced irrigation technologies while moderately expanding irrigated areas. For wheat and rice, less expansion is needed, and medium-efficiency water-saving technologies in newly developed irrigated areas could be enough to ensure food security under future climate conditions, meet water-saving policy targets and maximize investment returns.
Zhang Tianyi, a senior scientist at IAP, said the real question policymakers need to answer is which crops need irrigation, where irrigated area should be expanded, by how much, what technologies should be adopted and whether the investments are economically viable.
He noted that previous studies had largely focused on projecting changes in irrigated areas without fully accounting for interactions among irrigation technologies or between existing and newly developed irrigated areas.
"By integrating multi-source data and developing a new analytical framework, the study aims to provide more actionable scientific evidence for these specific investment decisions," he said.
The researchers emphasized that irrigation is not the only solution. Agricultural production is also influenced by crop variety breeding, cultivation management, land management scale and other factors. Irrigation investment should therefore be coordinated with the development of stress-tolerant crop varieties, climate-resilient cultivation practices and the construction of high-standard farmland.
Chen Huang, a researcher from Xiamen University in east China's Fujian Province, said the study drew on three independent datasets collected through different survey and research approaches. Despite their different sources, the model was able to 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 assessment of irrigation investment," he said. ■
