Intensification of rice production through different fertilizer management approaches under variable irrigation regimes

Water scarcity is the main problem in boro season in Bangladesh which limits growth and development of crop plants especially in rice crop. The field experiment was carried out at the Soil Science Field Laboratory of Bangladesh Agricultural University. The experiment was laid out in a split plot design with three replications. BRRI dhan29 was used as a test crop. Treatments were the combination of water saving techniques and integrated plant nutrient system (IPNS). There were four types of water management viz. I1: minimum irrigation, I2: normal irrigation, I3: continuous flooding and I4: alternate wetting and drying (AWD). The water management practices were placed in the main plot and nutrient management practices were introduced in the sub plots. There were five nutrient management practices viz. F1: 100% recommended fertilizer dose (RFD) chemical fertilizers (NPKSZn), F2: 75% RFD chemical fertilizers (NPKSZn) + 5 t ha-1 cowdung, F3: 75% RFD chemical fertilizers (NPKSZn) + 5 t ha-1cowdung slurry, F4: 75% RFD chemical fertilizers (NPKSZn) + 3 t ha-1 poultry manure and F5: 75% RFD chemical fertilizers (NPKSZn) + 3 t ha-1 poultry manure slurry. Minimum irrigation caused significant reductions in growth and yield of BRRI dhan29. On the other hand, AWD technique did not reduce the growth and yield of BRRI dhan29 in comparison to continuous flooding. Results also revealed that plant height, panicle length, number of effective tillers per hill and grains per panicle were significantly increased in I3F3 (continuous flooding with 75% RFD chemical fertilizers + 5 t ha-1 cowdung slurry) treatment compared to other treatments. Grain and straw yields of BRRI dhan29 showed higher values in I3F3 treatment. Nutrient uptake by BRRI dhan29 responded significantly in I3F3 treatment which was statistically similar to I3F4, I4F5, I2F5, I4F4 and I4F3 treatments. Finally it can be concluded that application of continuous flooding or AWD with 75% RFD chemical fertilizers + 5 t ha-1 cowdung slurry showed better performance than other treatments for maintaining better rice production. [J Bangladesh Agril Univ 2021; 19(1.000): 37-43]