Soil amendments in suppressing salinity effects on HYV rice cultivars

Abstract

Suppressing the harmful effects of salinity is a critical issue for expanding rice acreage in saline areas under demographic pressure and climate change contexts. In need of comprehensive information, this study evaluated the effectiveness of cowdung and gypsum (CaSO₄.2H₂O) for their individual and combined usages in ameliorating salinity stress for cultivation of Binadhan-8 (V₁), Binadhan-10 (V₂), and BRRI dhan47 (V₃) rice cultivars with standard fertilizer doses under irrigation with four salinity levels: fresh water (SL₁, control), 6 dS m^-1 (SL₂), 9 dS m^-1 (SL₃), and 12 dS m^-1 (SL₄). A pot experiment was laid in a Split-Split arrangement in a completely randomized design (CRD) with three factors (soil amendments, salinity levels, and rice cultivars) and three replications. The amendment treatments included: no amendment (T₁, control), cowdung @ 6 t ha^–1 (T₂), gypsum @ 150 kg ha^–1 (T₃), and combination of cowdung @ 6 t ha^–1 and gypsum @ 150 kg ha^–1 (T₄). SL₄ significantly (p£0.05) suppressed all attributes of the rice cultivars. Treatments T₃ and T₄ most effectively reduced salinity stress on the rice cultivars, which could tolerate up to 12 dS m^–1 irrigation-water salinity without significant yield loss, with T₃ performed the best. The generated information would help rice cultivation under irrigation with saline water, specifically in the coastal region having limited fresh water for irrigation.