Mitigating Impacts of Climate Change in Rice Production
Oriental Mindoro had always been blessed with favorable climate for crop production throughout the years. This dry season of 2009, however; rice farmers in Galapan, Oreintal Mindoro had great yield loss due to what they supposed to be a result of climate change.
Despite adopting recommended crop management practices, their harvest was as low as 2 tons per hectare, which was 50 percent lower than their usual yield, brought by unpredictable weather and higher frequency of rainfall.
According to Dr. Rolando T. Cruz, head of the Favorable Rice Environment program at the Philippine Rice Research Institute, the continuous cloudiness and rainfall as well as the low irradiance in Calapan could have reduced crop photosynthesis that could have resulted in lower crop biomass and grain yield.
“More problems like this may be expected if farmers themselves don’t help mitigate climate change,” warned Cruz.
RICE PRODUCTION AND CLIMATE CHANGE
In the chapter “State-of-the-Art Research and Development on the Interface among Rice Production, Water, and Forests” of the book Rice, Water, and Forests of the Asia Rice Foundation, the group of Cruz explained that farmers are not just preys of climate change because they, as rice cultivators, are also contributing to this.
While farm yield is decreased due to increased nighttime temperature associated with global warming, they continued, chances of climate change are also higher because 7f increased greenhouse gas emissions from rice production.
“It seems like we are reaping the effects of our agricultural activities that have contributed to climate change,” Cruz said.
Among these activities is the burning of rice straws and husks that is widely known to produce greenhouse gas methane that results in climate change.
According to a study of Olszyk in 1995, while increased concentrations of carbon dioxide through burning of rice crops residues might be beneficial to the enhancement of productivity of major rice varieties, this increases methane emission. Too much use of fertilizers and pesticides also results in the emission of N2O2, a greenhouse gas with global warming potential greater than that of methane in terms of longevity. And on top of all these is the fact that rice plants themselves emit methane.
PREVENTING CLIMATE CHANGE
The good thing is that there are ways to mitigate the negative impacts of rice production to the atmosphere to counter the negative repercussions of climate change in rice yield potential, wrote Cruz and his group in the same book.
Other than avoiding or minimizing the activities contributing to greenhouse gas emissions, the group believes that optimizing rice productivity is the best option to prevent yield loss due to climate change, and to mitigate climate change caused by rice cultivation.
They based this opinion on the 2002 study of Denier van der Gon et al. It was found that during the five years of successive tropical wet and dry seasons in the Philippines, rice plants with higher numbers of filled grain spikelets, or those that more closely reach their potential yield limits emitted less methane.
“But it is best if optimizing rice productivity will go hand in hand with optimum’ use of fertilizers and other inputs,” Cruz suggested.
The group also suggested that it is crucial to protect the forest, maintain their. watersheds, and have sound decisions before converting forests to rice areas, which can promote more agricultural activities that can lead to climate change due to atmospheric buildup of CO2.
However, “studies on how the rice sector can manage the natural resources as part of an effort to reduce or mitigate climate change are still lacking. But it is better to start with these suggestions now than wait until more Filipino rice farmers experience problems relating to it,” Cruz concluded.
And regarding Calapan and other areas where adverse effects of climate change are getting apparent. Cruz said that he is looking at the possibility of adjusting the planting calendar with careful consideration of the possible changes in crop-nutrient-pest management practices.