Alternate wetting and drying system for water management in rice

Abstract

Alternate wetting and drying (AWD) is aimed at saving water and maintaining comparable grain yields in the rice farming. It is a system of water management which involves the drying and rewatering of rice fields periodically. Rewatering is done to about 5 cm depth after the water level has fallen to 15 cm soil depth. This practice is repeated during the whole crop growing period except the flowering stage where the water level is maintained at up to 5 cm water depth. In order to get the best out of the AWD, it is important to select the right soil type, maintain the optimum plant population, apply nitrogen timely, and maintain the correct duration of wetting and drying. Fields under AWD may be ponded with water for 2-3 weeks for the cultural control of weeds. A good coordination among stakeholders may assist in attaining the maximum benefits from AWD. AWD also reduces arsenic in the rice grains and methane emission from the rice fields. It improves growth of root and canopy structure. Correct implementation of AWD can impart intended outputs on sustainable basis to tackle water scarce condition without losing rice productivity.