Integrated nitrogen management of monsoon rice under two different plant spacings

Abstract

Proper management practices such as plant spacing and nutrient management are the most effective means for increasing yield of rice. To date no single spacing or nutrient management has been recommended as ideal for all field conditions for a particular variety which must be established experimentally. The current experiment was, therefore, conducted to study the effect of integrated nitrogen management and plant spacing on the growth, yield and yield components of monsoon rice (rainfed transplanted rice) cv. BRRI dhan41. The experiment consisted of the following sets of treatments: factor (A) integrated nitrogen management: control, i.e., no urea super granule (USG), prilled urea (PU) and poultry manure (PM) (T₁), 1.8 g USG 4 hill^-1 (T₂), 2.7 g USG 4 hill^-1 (T₃), PM at 5 t ha^-1 (T₄), PM at 7.5 t ha^-1 (T₅), 1.8 g USG 4 hill^-1 + PM at 5 t ha^-1 (T₆), 2.7 g USG 4 hill^-1 + PM at 7.5 t ha^-1 (T₇), 1.8 g USG 4 hill^-1 + PM at 2.5 t ha^-1 (T₈), 2.7 g USG 4 hill^-1 + PM at 3.75 t ha^-1 (T₉), recommended dose of PU i.e., 240 kg ha^-1 (T₁₀), 1/2PU + PM at 5 t ha^-1 (T₁₁), full dose of PU + PM at 7.5 t ha^-1 (T₁₂), 1/2 PU + PM at 2.5 t ha^-1 (T₁₃) and full dose of PU + PM at 3.75 t ha^-1 (T₁₄); and factor (B) plant spacing: 25 cm × 15 cm (S₁) and 25 cm × 20 cm (S₂). The experiment was laid out in a randomized complete block design with three replications. Integrated nitrogen management showed significant effect on all the yield and yield contributing characters except number of non-effective tillers hill^{- 1}, panicle length and weight of 1000 grains. The results revealed that the highest grain yield (3.67 t ha^-1) was obtained from T₆ and the lowest grain yield (1.39 t ha^-1) was obtained from T₁. All the yield and yield contributing characters were significantly affected by plant spacing except number of total tillers hill^-1, number of non-effective tillers hill^-1, panicle length and weight of 1000 grains. The spacing 25 cm × 20 cm resulted in higher grain yield (3.05 t ha^-1) than the spacing 25 cm × 15 cm. Grain yield was affected by the interaction of integrated nitrogen management and plant spacing. The highest grain yield (3.74 t ha^-1) was recorded with the interaction between T₆ and S₂ while the lowest one (1.36 t ha^-1) was obtained from T₁ and S₁ combination. Therefore, for higher yield monsoon rice cv. BRRI dhan41 should be planted following 25 cm × 20 cm spacing and fertilized with 1.8 g USG 4 hill^-1 + 5 t ha^-1 PM to meet nitrogen requirement.