Effect of Nitrogen Rates and Planting Methods on Growth and Yield of Late Season Aus Rice in the Southwestern Coastal Region of Bangladesh

Abstract

The current study was conducted during the late aus season (June-September) of 2023 at the Prof. Dr. Purnendu Gain Field Laboratory of the Agrotechnology Discipline of Khulna University, Khulna. The primary aim of this research was to assess the impact of varying nitrogen rates (0, 52, 69, 86, and 104 kg nitrogen ha⁻¹) on the growth and yield of the BRRI dhan48, utilizing four different sowing methods: broadcasting, line sowing, hill sowing, and transplanting. The experimental design employed a factorial randomized complete block design with three replications. The following data were collected: plant height (cm), tiller number m⁻², panicle m⁻², panicle length, filled grains panicle⁻¹, unfilled grains panicle⁻¹, 1000-grain weight, grain yield, straw yield, biological yield and harvest index. A combined analysis was performed to evaluate the interaction between planting methods and nitrogen rates. The findings indicate that the transplanting method with 86 kg N ha⁻¹ (125%) nitrogen significantly enhanced plant height (82.63 cm), panicle m⁻² (847.33), number of filled grains per panicle (111.00), 1000-grain weight (31.39 g), grain yield (4.06 t ha⁻¹), and harvest index (44.99%) when compared to the broadcasting, line, and hill sowing methods. Increasing nitrogen rates up to 104 kg N ha⁻¹ (150%) led to a significant rise in plant height, chlorophyll content index, and straw yield. The transplanting method resulted in a notable rise in .plant height, number of tillers, chlorophyll content index, panicle length, 1000-grain weight, grain yield, and harvest index over hill sowing, line sowing and broadcasting excluding straw yield. Itcan be concluded that application of 125% N (86 kg ha⁻¹) with transplanting methods is suitable for the cultivation of aus rice (BRRI dhan48) during late season in southwestern coastal Bangladesh.