LAUSR

ABSTRACT Salt-affected soils expand around the world and become a critical handicap for high crop yield. Saline-sodic soil contributed a major portion in salt-affected soils. Such types of soils have a sizable amount of Na+ in nutrient medium and that reduce the K+ uptake in plants. A hydroponic experiment was performed to investigate the ameliorative effect of different doses of potassium fertilizer (K1 = 0.3, K2 = 0.6 and K3 = 1.2 mM L−1) on rice (Oryza sativa L.) under different ECw (6 dS m−1) and SARw [12 and 24 (mmol L−1)1/2] levels. Application of K+ at elevated levels under saline-sodic conditions improved the concentration of anti-oxidant enzymes, plant physiological, and biochemical attributes by improving the K+: Na+ ratio in plant tissues. Total phenolic content, total soluble protein, and soluble sugar content of rice plant were increased with an increase in potassium dose and saline-sodicity. Maximum K+: Na+ ratios, 4.13 and 2.0 were observed in shoot and root, respectively upon application of K+ at 1.2 mM L−1 in a solution having ECw: SARw level of 6: 12. This study suggested that application of potassium at elevated levels (1.2 mM L−1) has enhanced the rice growth by reducing the harmful effect of Na+ salts on plant physiology, biochemical attributes, and anti-oxidant enzymes under specific saline-sodic conditions.