Controlled Irrigation With Insufficient Water
In areas where there is insufficient water, farmers may now ensure good yield from their rice plants by following the controlled irrigation technique (alternate wetting and drying) or by planting aerobic rice. Even in areas with sufficient irrigation water, farmers may also opt to decrease their water requirements by following the said technique without adverse effect on their yields.
Normally, farmers believe that continuous flooding is the key to good rice yield but this is not always the case as shown by the results collaborative studies conducted by Phi Rice, the National Irrigation Administration (NIA) and the International Rice Research Institute (IRRI).
Controlled Irrigation(CI) or alternate wetting and drying technology allows ricefields to dry up for some time. The rice plants are irrigated only when the soil moisture near the root zone is almost gone.
How would you know that the soil moisture is almost gone? PhilRice researcher Jovino de Dios said all the farmers have to do is to install a plastic pipe (about 1 foot in diameter, one foot deep into the soil) in a strategic location in the rice field so that they can monitor the soil moisture regularly. When water is no longer seen inside the pipe, it’s time to bring in irrigation water to rice field.
Results of experiments conducted in Tarlac and Nueva Ecija showed no significant difference in yield between continuously flooded plants and those subjected to controlled irrigation.
Ver Gallardo, one of the farmer-cooperators in Nueva Ecija, said controlled irrigation enabled him to save P1,000 in diesel fuel in one season. Greg Meriales, also from Nueva Ecija, likewise noted the efficiency of controlled irrigation.
Aside from controlled irrigation, farmers in water-stressed areas would do well to use rice varieties that can grow well with less water and still produce good yield. These varieties are also called aerobic rice.
Among the aerobic rice varieties bred by PhilRice are PSB Re 14, PSB Re 12. PSB Rc24, PSB Rc36, PSB Rc38, PSB Rc40, and PSB Rc42. These varieties have a yield potential of 6t/ha. The varieties Apo, UPLRI-5, and Magat are also aerobic rice varieties.