Influence of Split Potassium Fertilizer Application on Yield of Short-duration Transplanted Aman Rice Varieties

Split application of potassium fertilizer generally enhances the yield and yield-contributing traits of rice. To evaluate its effect on the yield performance of transplant (T.) aman rice, a field experiment was conducted at the Agronomy Field Laboratory of Bangladesh Agricultural University, Mymensingh, from June to October 2024. The study involved five T. aman rice varieties-BRRI dhan56, BRRI dhan66, BRRI dhan71, BRRI dhan75, and Binadhan-7; and employed four split applications of potassic fertilizer-Control (no potassic fertilizer), basal application of full dose of potassic fertilizer, ½ as basal + ½ at active tillering stage, 1/3rd as basal + 1/3rd at active tillering stage + 1/3rd at panicle initiation (PI) stage. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Results showed that among the varieties, BRRI dhan66 produced the highest grain yield (4.718 t ha-1) due to highest number of total and effective tillers hill-1 and highest number of grains panicle-1. Split application of potassic fertilizer as 1/3rd basal + 1/3rd at active tillering stage + 1/3rd at PI stage produced the highest grain yield (4.907 t ha-1) due to highest number of total and effective tillers hill-1, highest number of grains panicle-1 and heaviest 1000-grain weight. Rice variety BRRI dhan66 with three times split application of potassic fertilizer as 1/3rd basal + 1/3rd at active tillering stage + 1/3rd at PI stage produced the highest grain yield (5.39 t ha-1) where 68.44% yield was increased than the interaction of rice variety BRRI dhan56 with control (3.20 t ha-1). Based on the study results, applying potassic fertilizer to BRRI dhan66 in three equal splits-one-third at basal, 1/3rd basal + 1/3rd at active tillering, and 1/3rd at panicle initiation-may be recommended to optimize grain yield in T. aman rice.