Adoption and economics of alternate wetting and drying water management for irrigated lowland rice

To counteract the increasing unavailability of water for agriculture, the International Rice Research Institute (IRRI) and its national agricultural research and extension system (NARES) partners have worked together to develop and promote the alternate wetting and drying (AWD) water management technology. In this paper, we review progress in the development and dissemination of AWD in several Asian countries, and provide evidence of its extent of adoption and economic impact. AWD involves the partial drainage of rice fields, which is done by irrigating the fields to the desired depth and then re-irrigating after some time, when the water dissipates. To guide proper implementation, a simple, very low cost, farmer-friendly tool-a perforated field water tube-was devised. Demonstration trials and training have been conducted in eight countries in Asia, with large scale adoption in the Philippines, Vietnam and Bangladesh. AWD has reduced irrigation water input by up to 38% with no yield reductions if implemented correctly. Water pumping expenses and fuel consumption decrease also, thus increasing farmers' income by 38% in Bangladesh, 32% in the Philippines, and 17% in southern Vietnam, based on with and without AWD comparison. The investment to develop and disseminate the AWD technology has a high rate of return, with benefit-cost ratio of 7:1. The evidence of economic benefits at the farm level when aggregated up more than compensates for the total research investments made to develop and disseminate the technology. Successful NARES partnerships and strong farmers' groups were critical factors in the validation and dissemination of the technology. AWD has also been successfully integrated into national government programs, which also facilitated the widespread adoption of the technology in these countries. (C) 2014 Elsevier B.V. All rights reserved.