Effect of Gypsum Application on Salinity Stress Mitigation at Different Growth Stages of Boro Rice cv. BRRI dhan47

Salinity is a critical abiotic stress in Bangladesh, severely limiting rice growth and yield due to the crop's high sensitivity to saline conditions. While gypsum application is known to mitigate salinity stress, its effects on different growth stages of rice under varying salinity levels remain inadequately explored. To address this gap, a study was conducted in the net house of the Department of Agronomy, Bangladesh Agricultural University, Mymensingh (24.75°N, 90.5°E), during the Boro season (November 2023 to April 2024). The experiment employed a Completely Randomized Design (CRD) with four salinity levels (0, 4, 8, and 12 dS m-1) and three gypsum levels (0, 1, and 2 g gypsum kg-1 soil) applied across three growth stages: tillering, panicle initiation, and flowering. Results demonstrated that high salinity (120 mM NaCl) significantly reduced plant height (9.63%), tiller number (7.8%), leaf area index (19.32%), and grain yield (24.19%) compared to the control. In contrast, gypsum application at 2 g kg-1 soil effectively mitigated salinity stress, enhancing leaf area index (5%), root length (2%), and grain yield (29.55%) over the control. Moreover, it recovered almost 8% grain yield under highly saline conditions. The findings highlight gypsum's potential as a practical and effective soil amendment for improving rice performance in saline environments. Future research should investigate the long-term effects of gypsum application under field conditions and explore its integration with complementary agronomic practices for sustainable rice production.