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SEARCA-IRRI project examines vulnerability of rice production to climate change through crop simulation modeling

Published on 7 August 2014 KC3 News

LOS BAÑOS, Philippines – Rice is the most important food crop in the Philippines. It is the staple food item in the diet of about 80 percent of the Filipinos, and the value of its annual production is close to PHP 2 billion. According to the International Rice Research Institute (IRRI), from the 5.4 million hectares of arable land in the country, 81 percent (4.4 million hectares) is devoted to rice production. It also provides livelihood to more than two million households, along with millions of farm laborers and tens of thousands of dealers and traders. Thus, the Philippine rice sector has always been the center of the government’s agricultural policies, which focus on promoting rice self-sufficiency and increasing farmers’ income while making rice prices affordable to consumers.

However, rice production in the Philippines faces a number of constraints, namely: growing population, declining land area, high cost of inputs, and poor drainage and inadequate irrigation facilities. Moreover, due to the Philippines’ location, the rice sector becomes highly vulnerable to climate change, which severely affects crop production. Successive heavy rains cause severe drainage problems in paddy fields, thus resulting in a significant reduction in rice yield and quality. 

The vulnerability of rice production to climate change and climate variability is an important concern that needs to be addressed. With this in mind, the Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) in collaboration with IRRI implemented a study titled “Impact on Climate Change on the Philippine Rice Sector: Supply/Demand Projections and Policy.” The study analyzed the effects and impacts of climate change on rice production in the Philippines and assessed the effects of global warming on rice productivity. Crop yields were estimated and compared for different possible climate scenarios (i.e., incremental increases in temperature change in rainfall volume and distribution and increase in atmospheric carbon dioxide concentration). Furthermore, the study established data on the sensitivity of rice yield to weather variables, analyzed the risks associated with climate-related hazards, and assessed the availability of and access to coping measures in the major rice growing areas and the level of adaptive capacity of the rice production systems. A survey of key climate change adaptation measures and good practices in rice production was therefore conducted.

The project was led by Dr. Felino P. Lansigan, Professor at the Institute of Statistics, College of Arts and Sciences, University of the Philippines Los Baños (UPLB). Other members of the research team are Dr. Mercedita A. Sombilla, Mr. Arnold R. Salvacion, and Ms. Anna H. de Guia. The study sites were the top rice-producing provinces in the country, including Ilocos Norte, Cagayan, Isabela, Nueva Ecija, Laguna, Camarines Sur, and Iloilo.

Crop simulation modeling and analyses showed that temperature increase is expected to result in rice yield reduction. Global warming is likely to lead to drier conditions, which will result to a decrease in area planted, hence, affecting rice production. Despite their vulnerability to climate hazards, the study areas continue to be the top rice-producing provinces in the Philippines. This indicates that these areas have high adaptive capacity. Farmers in these provinces have successfully put into practice adaptation measures and good agricultural practices (GAP) to cope with climate change. Some of these good practices include adjusting the crop calendar, updating of weather-based dynamic cropping calendar based on crop yield probabilities, planting more resistant or climate stress-tolerant crop varieties, and employing crop diversification and crop-livestock integration.

The extent of each climate hazard, exposure, and adaptive capacity varies spatially due to topography, climate type, and archipelagic nature of the Philippines. The effects and impacts of climate hazards on rice production systems in the Philippines also vary. Provinces with rice surpluses or shortages are spatially differentiated in relation to climate hazards. Most provinces with rice surplus are areas that are highly vulnerable to climate hazards and are less populated, while provinces with rice shortage are less vulnerable and densely populated.

The study recommends the following: (1) to define the plausible climate scenarios downscaled to specific provinces, (2) to study the interprovincial or regional trading of rice among areas with surpluses and shortages in the context of food security under a changing climate, and (3) to incorporate the suite of the available climate change adaptation measures available in the integrated crop management strategies in order to increase adaptive capacity of rice farmers.