The Philippine Rice Research Institute has recommended in its advisory the practice of controlled irrigation or alternate wetting and drying to optimize the use of irrigation water.

Jovino de Dios, head of the PhilRice Agronomy, Soils, and Plant Physiology Division, said advisory that water should be brought into the rice paddies only when the soil moisture is about to leave the root zone of the rice plant. This is done by placing a cylindrical object 15-centimeter deep in the wet season or 20-centimeter deep in the dry season from the soil surface, the advisory said.

The CI technology was developed by PhilRice, International Rice Research Institute, and the National Irrigation Administration from years 2001 to 2004.

PhilRice said in the advisory that the CI method allows farmers to bring in irrigated water to thin fields once a week. Farmers can stop irrigating their fields when water depth reaches a five-centimeter depth from the soil surface.

It added that the technology also stabilizes soil and plant base thereby minimizing crop lodging, facilitates farm mechanization, and corrects some problems on soil nutrient imbalances such as zinc deficiency, especially if draining is done during the tillering stage of the rice plant.

Rolando Cruz, PhilRice's program leader on favorable environments, said that using such technology will not pose problems because it does not induce plant water stress and reduce rice crop growth and yield.

A PhilRice study also shows that CI can reduce the amount of water used in irrigated lowland rice without reducing yield.*

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