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Alternate wetting and drying irrigation (AWD) has been reported to save water compared with continuous flooding (CF) in rice cultivation. However, the reported effects on yield varied greatly with soil type, cultivars, and detailed agrohydrological characterization is often lacking so that generalizations are difficult to make. This study quantified the impact of AWD on rice (Binadhan-8 and Binadhan-10) yield, water productivity and irrigation water savings. The irrigation treatments comprised of: Normal farmer’s practice (continuous ponding, 3-5 cm) [T1]; alternate wetting (irrigation by 5 cm) and drying (AWD) for 3 days after disappearance of ponded water (DOPW) [T2]; AWD for 5 days after DOPW [T3]; and a combination [T4].
The grain yields varied from 3.9 to 4.4 t ha–1 with no significant difference in yield attributes (except 1000 grain wt.), grain yields and straw yields between AWD and CF. The productivity of water in AWDs was about 6 - 40% higher than that of CF, and the water savings in AWDs compared to CF were 22 – 35%. Alternate wetting and drying for 5 days can save substantial amount of irrigation water without sacrificing yield. This practice can be adopted for cultivating those cultivars for sustainable irrigation management.
Keywords: Boro rice, Water management, Water productivity, Alternate wetting and drying irrigation.