Abstract
A study was conducted at the experimental farm of Bangladesh Rice Research Institute, Gazipur during T. Aman 2001 to 2003 and Boro 2002 to 2004 seasons in order to find out the effect of planting method and water management on the water requirement, yield, water productivity and economic performance of rice. The study was carried out with three planting methods such as direct seeded rice (DSR), wet seeded rice (WSR) and transplanted rice (TPR) with six different water management practices such as 2-5 cm continuous standing water (T1), Irrigation was applied 5 days after disappearing of 5 cm standing water (T2), Irrigation was applied 7 days after disappearing of 5 cm standing water (T3), Irrigation was applied 10 days after disappearing of 5 cm standing water (T4), saturation (alternate wetting and drying) (T5) and Similar to T1 but withholding water for 10 days in the early vegetative and reproductive stages of the crop (T6). In Aman season, DSR and WSR required 240 to 250 mm water for land preparation, whereas, for TPR, it was about 280 to 290 mm. In Boro season, only 50 mm water was required as pre-sowing for DSR, 240 to 250 mm water was required for land preparation of WSR and 280 to 288 mm water was required for land preparation of TPR. Total water required for DSR and WSR varied from 819 to 1203 mm and for TPR 927 to 1276 mm in Aman seasons, respectively. DSR and WSR saved 8.50, 7.87 and 16.54% water compared to TPR. The mean water productivity of DSR, WSR and TPR in T. Aman seasons varied from 4.48 to 5.24, 4.46 to 5.07 and 3.50 to 3.93 kg/ha/mm, respectively. The results indicated that DSR and WSR produced 17.36% and 16.75% higher yield than TPR in T. Aman 2001, 14.35% and 13.85% higher yield than TPR in T. Aman 2002 and 8.35% and 7.12% higher yield than TPR in T. Aman 2003, respectively. The average number of panicles/sqm of DSR, WSR and TPR were 266, 268 and 244 in 2001; 266, 264 and 243 in 2002 and 286, 286 and 289 in 2003 for T. aman. The mean values of unfilled spikelets of DSR, WSR and TPR under all water management practices were 15.63, 15.57 and 18.64% and that of under the planting methods were 12.60, 19.25, 17.45, 20.56, 14.31 and 15.51%, respectively. Plant height, straw yield and harvest index of BR11 under DSR, WSR and TPR varied from 118 to 116, 118 to 116, and 117 to 113cm; 7971 to 7801, 8004 to 7444 and 7772 to 6987 kg/ha and 0.038 to 0.035, 0.038 to 0.035 and 0.360 to 0.035, respectively during the study period. The results revealed that DSR and WSR performed better than TPR in all respect. Direct seeded and wet seeded rice matured 12 to 16 days earlier and gave higher benefit cost ratio than transplanted rice in Aman season. Direct seeded and wet seeded rice saved about 27.59% and 5.18% water in Boro 2002, 25.11% and 3.81% water in Boro 2003 and 30.77% and 6.55% water in Boro 2004, respectively. The mean water productivities of DSR, WSR and TPR were 7.41, 5.46 and 4.35 in 2002; 6.58, 4.98 and 4.39 in 2003 and 8.00, 5.85 and 4.65 in 2004, respectively. On an average, DSR and WSR yielded 19.33% and 18.90% in Boro 2002, 15.95 and 14.15% in Boro 2003 and 18.00 and 17.13% in Boro 2004, which were higher than TPR. So, it may be inferred that DSR produced higher yield (19.33%) than TPR. Thus, DSR saved higher percent of water (30.77%) than TPR which may be considered as the best rice planting method. Treatment T2 is found to be the most profitable and suitable water management practice which used less amount of water compared to T1 in Boro season. The average number of panicles/sqm were 285, 281 and 244 in 2002; 276, 279 and 240 in 2003 and 287, 283, 251 in 2004 for DSR, WSR and TPR, respectively. The effects of planting methods as well as water on grains/panicles both in Aman and Boro seasons in all the study years were non significant. The mean percentage of unfilled spikelets of DSR, WSR and TPR were 14.60, 16.36 and 19.76 in 2002; 14.30, 14.86 and 16.10 in 2003 and 19.83, 21.22 and 26.44 in 2004, respectively. Plant height, straw yield and harvest index of BRRI dhan28 under DSR, WSR and TPR varied from 81 to 77, 80 to 76 and 78 to 74 cm; 7441 to 6939, 7615 to 7416, and 6569 to 6371 kg/ha and 0.403 to 0.378, 0.384 to 0.369 and 0.382 to 0.373, respectively. Direct seeded and wet seeded rice matured 14 to 17 days earlier and gave Tk. 3535 to 8380/ha and Tk. 2642 to 7152/ha more return than transplanted rice in Boro season. Direct and wet seeded rice gave benefit cost ratio in comparison to transplanted rice. It may be, inferred that in all the cases, the performance of DSR and WSR are better than TPR. Therefore, farmers can cultivate rice by DSR and WSR planting methods to get maximum benefit from rice farming.