Effect of Ground Water Irrigation on Paddy Rice Yield in Maligaya, Philippines

Abstract

Air and water temperatures are important climatic variables influencing rice yields through the interaction of pests and nutrients. The Philippine Rice Research Institute (PhilRice) in Maligaya, central region of Luzon island, stated that the Philippines could attain rice sufficiency if farmers' average yield increases to at least 1 t/ha. It is generally said that decreasing the minimum air temperature in the rice canopy could make a yield increase possible in the Philippines. Instead, results showed that the timing of irrigation water application using a shallow tubewell pump in Maligaya could not decrease canopy air temperature. However, the temperature of the standing or flooding water in the field was reduced using pumped water or ground water irrigation compared with the conventional irrigation where water came from irrigation canals, and the lower temperature of the standing water resulted in an increase in rice yield from 7.27 to 8.58 t/ha for PSB Rc28 rice cultivar and from 3.08 to 4.02 t/ha for New Plant Type IR66106-5-3-2-3. Based on this result, this study recommends that rice growers irrigate using pumped water or ground water from 15: 00 to 17: 00 with a standing water level of 5 cm during the reproductive stage to have a lower water temperature at night for better efficiency of water and resistance to white heads.