A joint research team from China and the Philippines has recently found that converting rainfed rice fields into irrigated areas could significantly reduce the climate sensitivity of rice yields and help improve the country's rice self-sufficiency under future climate conditions.

The study, published in Agricultural Water Management on November 4, offers scientific evidence that may support the Philippines' future irrigation planning and climate adaptation strategies.

Food security is a basic human right and an important foundation of national security. In recent years, cooperation between China and the Association of Southeast Asian Nations (ASEAN) on food security has become increasingly important through documents such as the China-ASEAN Free Trade Area 3.0 Upgrade Protocol, the Plan of Action to Implement the ASEAN-China Comprehensive Strategic Partnership (2026–2030), and the China-ASEAN Joint Statement on Food Security Cooperation.

At the 2026 China (Henan)–ASEAN Food and Agriculture Cooperation and Development Conference held on October 30, leaders from China and ASEAN countries emphasized deeper agricultural sci-tech cooperation in smart agriculture, water-saving irrigation, meteorological early warning, and agricultural supply chain resilience.

Rice is a staple food and a politically sensitive crop across ASEAN, closely linked to social stability and economic development. Under global warming, extreme weather events including heatwaves, droughts and floods are posing growing challenges to rice production.

In 2024, drought associated with an early El Niño event and subsequent typhoons caused a decline in the Philippines' rice self-sufficiency rate to 71.7 percent, the lowest level in the past 37 years. Consequently, the Philippine Department of Agriculture declared a "Food Security Emergency" in February 2025. Therefore, enhancing the climate resilience of rice production has become a key task for the Philippines.

To assess how irrigation expansion may affect future rice production, Dr. ZHANG Tianyi from the Institute of Atmospheric Physics of the Chinese Academy of Sciences, together with partners from the University of the Philippines Los Baños, the Philippine Rice Research Institute, and Huazhong Agricultural University, analyzed 11,003 provincial-level rice yield data from the Philippines. The team evaluated the potential effects of converting rainfed rice to irrigated rice on national yield and self-sufficiency under future climate scenarios.

Statistical analysis showed that irrigated rice yield during the dry season was 28% less sensitive to each degree of warming than rainfed rice, declining from 5.6%/℃ yield reduction for rainfed rice to 4.0%/℃ reduction for irrigated rice.

Associate Professor DENG Nanyan of Huazhong Agricultural University said that irrigation can significantly enhance the climate resilience of Philippine rice, making it an important measure for safeguarding food security.

The researchers further estimated the adaptation potential of expanding irrigation under future climate change. The model suggested that the current pace of irrigation expansion in the Philippines would be insufficient to offset projected yield losses.

"Raising the provincial irrigation fraction to at least 60% could potentially offset the negative impact of future climate change on rice yield, while increasing the irrigation fraction to 100% could raise the national rice self-sufficiency rate to about 87%," ZHANG said.

Additional Pressure

However, the researchers also warned that expanding irrigation may place additional pressure on local water resources.

Professor Rubenito M. Lampayan of the University of the Philippines Los Baños said that the Philippines should not only expand irrigated areas where appropriate, but also promote water-saving practices such as alternate wetting and drying irrigation.

"We plan to prepare a policy advisory report based on the study for submission to the Philippine Department of Agriculture and the National Irrigation Administration, aiming to provide scientific support for future irrigation planning," he said.

The year 2026 is the 5th anniversary of the ASEAN-China Comprehensive Strategic Partnership and the 35th anniversary of ASEAN-China dialogue relations. Deepening food security collaboration is an important step toward building a closer China-ASEAN connection with a shared future and strengthening regional and global food security.

The study was supported by the joint Intergovernmental Cooperation Project on Scientific and Technological Innovation between the Ministry of Science and Technology of China and the Department of Science and Technology of the Philippines (2025YFE0110600), the National Natural Science Foundation of China (42575205) and the Asian Cooperation Fund.

Through such joint research, policy dialogue and technology exchange, China will continue to provide diplomatic and institutional support for ASEAN food security. By linking scientific evidence with regional cooperation frameworks, the study highlights how scientific irrigation planning can contribute to strengthened food security in the Philippines and across Southeast Asia.