Effect of Water Management Practices on Rice Yield, Water Productivity and Water Savings under Irrigated Rice Paddy Ecosystem

A field experiment was carried out during the Boro season 2013 to find out the effects of water management practices on rice yield performance and water productivity index at Old Brahmaputra flood plain paddy land, Muktagacha, Mymensingh. The experiment was laid out in randomized complete block design (RCBD) with six (6) irrigation treatments. Two treatments, T 1 and T 3 were kept under continuous standing water levels (10 cm and 5 cm respectively) while in treatment T 5 irrigation water was supplied for 1 st 3 weeks then followed mid season drain out and re-flooded at flowering stage. Three alternate wetting and drying irrigation treatments, T 2 , T 4 and T6 were selected in which irrigation water was applied when water level dropped 20cm, 10cm and 15cm below ground level, respectively. All the irrigation treatments significantly affected the rice yield and yield contributing parameters. The study revealed that the highest grain yield (5950 kg ha -1 ) was found in treatment T 5 which was identical with AWDI treatment T 4 (5820 kg ha -1 ) followed by AWDI treatment T 6 (5460 kg ha -1 ). On the contrary, rice yield of 3350 kg ha -1 , 4470 kg ha -1 and 4810 kg ha -1 were found in the treatment T 1 , T 2 and T 3 , respectively. It was found that AWDI treatment T 2 showed maximum water savings (15.1%) followed by T 6 (11.3%), T4 (7.59%) and T 5 (3.8%), however rice yield in the treatment T 2 (4470 kg ha -1 ) was significantly lower compared to T 6 , T4 and T 5 treatment. Therefore, it may be inferred that treatment T 4 (AWDI; irrigation when water level fell 10 cm from ground level), T 5 (Irrigation for 1 st 3 weeks, then mid-season drain out and re-flooding at flowering) and T 6 (AWDI; irrigation when water level fell 15cm from ground level) would be the feasible choice for the water savings, higher rice yield as well as maximum water productivity index (0.478, 0.472 and 0.467, respectively) for sustaining rice farming during the dry Boro season in Bangladesh. J. Environ. Sci. & Natural Resources, 9(2): 79-84 2016