Potassium (K) is a major nutrient limiting productivity of modern rice varieties, yet its efficient utilization remains a challenge under intensive cultivation. A field experiment was conducted during the 2021–22 and 2022–23 dry (Boro) seasons at Sher-e-Bangla Agricultural University to evaluate potassium uptake and use efficiency of BRRI dhan100 under integrated nutrient management. Seven fertilizer treatments, including recommended practice, increased or reduced K levels, soil-test-based fertilization, cowdung incorporation, and control, were arranged in a randomized complete block design with three replications. Grain yield, yield components, nutrient uptake, and K use efficiency indices were measured.
Integrated nutrient management with cowdung (K5) consistently produced the highest grain yield (6.75 t ha⁻¹) and improved yield attributes across both seasons. Treatments receiving balanced K fertilization showed higher K uptake and efficiency compared with K-deficient plots. Agronomic efficiency and recovery efficiency were notably enhanced under integrated nutrient supply. Results indicate that combining inorganic fertilizers with organic amendments improves potassium use efficiency, sustains soil fertility, and enhances productivity of modern rice.
Therefore, integrated nutrient management involving recommended fertilizer dose plus cowdung is suggested for sustainable cultivation of BRRI dhan100 during the Boro season.