Rice plants need less water than normally used — DA-PhilRice

Rice plants need not "wallow" in waterlogged condition, as is traditionally practiced.

"Rice paddies in water for a long time is wasteful," said Jovino de Dios, head of the PhilRice Agronony, Soils, and Plant Physiology division.

Instead, he recommends to farmers the use of controlled irrigation (CI) or alternate wetting and drying to optimize the use of irrigation water. The CI technology was developed by PhilRice, IRRI, and the DA-National Irrigation Administration (NIA) during four years (2001-2004) of research.

De Dios said water should be brought into the rice paddies only when the soil moisture is about to leave the root zone of the rice plant by placing a cylindrical object 15 centimeters deep in the wet season or 20 cm deep in the dry season from the soil surface.

The CI method allows farmers to bring in irrigation water to thin fields once a week. Farmers can stop irrigating their fields when water depth reaches a 5-cm depth from the soil surface, De Dios said.

The technology also stabilizes soil and plant base, thereby minimizing crop lodging, facilitates farm mechanization, and corrects some problems on soil nutrient imbalances. Moreover, it reduces farm inputs such as oil, fuel, and labor.

Dr. Rolando Cruz, PhilRice program leader on favorable environments, emphasized that "if the technology is followed, it should not induce plant water stress and reduce rice crop growth and yield."

A PhilRice study also showed that CI can reduce the amount of water used in irrigated lowland rice without reducing yield, as attested by Nueva Ecija farmer Greg Meriales. — RAF