Spatial and Temporal Variation of Climatic Elements and its Impact on the Yield of Rice (Oryza sativa L.) in Masbate, Philippines

As a C-3 crop, the growth and development of rice is greatly affected by the fluctuations and occurrences of climatic extremes particularly at critical growth stages. This study was conducted to investigate the temporal and spatial variation of climatic elements and assess its impact on the yield of rice in the province of Masbate. Remotely-sensed climatic data from 1991 to 2020 and data from the lone synoptic weather station of PAGASA in Masbate were used in this study. Yield production data were sourced from Philippine Statistics Authority (PSA) and Provincial Agriculture Office of Masbate (PAO-Masbate). Temporal analysis revealed that the direction and magnitude of trends of various climatic elements in the province of Masbate differ annually and seasonally. The only significant trends, however, are that of the decreasing trend of Tmax and Tmean. Except for rainfall, temporal variation of Tmin, Tmax, and Tmean is negatively and significantly correlated to rice yield. In general, 1 degrees C increase would result in 10-24% reduction in yield. Spatial analysis revealed that, except for solar radiation, a significant difference was detected in rainfall and temperatures in various areas in Masbate. These differences in localized climate could be due to mountain ranges and other characteristics of land surface, such as land use and land cover. While correlation analysis showed that the yield and the amount of rainfall in Masbate are not significantly related, data during 1991-2019 show that rainfall is potentially one of the most limiting factors in the province's rice production. On top of the increasing trend of the number of dry days, the amount of rainfall is just adequate to supply the minimum requirement of rice during wet season but a bit short during dry season. These scenarios indicate that drought is more of a problem rather than waterlogging or flooding in Masbate's rice production, especially during dry season. Aside from rainfall, temperature extremes greatly affect rice productivity in Masbate. There are months in Masbate when recorded temperatures exceed that of the optimum requirement of rice crop. To minimize the negative impacts of drought and temperature extremes in the rice production in Masbate, more irrigation facilities should be established considering that 70% of rice production is rainfed, a cropping calendar based on the climatic data must be followed, and planting climate change-ready rice cultivars such as those tolerant to drought and high temperatures must be considered.