Effect of Alternate Wetting and Drying (AWD) Irrigation for Boro Rice Cultivation in Bangladesh

Abstract

A field experiment was conducted at the Bangladesh Rice Research Institute to find out possible effects of alternate wetting and drying irrigation (AWDI) on the yield, water use and water use efficiency (WUE) of Boro rice. The experimental plots were laid out with 2 factors RCBD combining two modern varieties of rice viz., BRRI dhan29 and BRRI hybrid2, which received four irrigation treatments randomly and was replicated thrice. The treatments ranged from continuous submergence (T 1) of the field to a number of delayed irrigations (T 2 , T 3 and T 4) denoting application of 5cm irrigation water when water level in the perforated PVC pipe fell 15, 20 and 25cm below ground level (G.L.), respectively. The study revealed that treatment T 1 attributed by the highest total water use (122.2cm) and the lowest WUE (84.34kg/ha/cm) produced the lowest grain yield (4.71t/ha). Treatment T 2 , on the contrary, gave the highest yield (5.69 t/ha) and consequently the second highest WUE (85.55 kg/ha/cm) indicating quite a large water saving (15cm) compared to treatment T 1 . The yields in treatments T 3 (5.45 t/ha) and T 4 (5.27 t/ha) were significantly lower at 1% level of significance compared to that of treatment T 1 . Significant effect was found either for the treatment or for the varieties on the number of effective and total tillers hill -1, plant height, number of effective tillers hill-1, grain yield, straw yield, biological yield and harvest index.