Influence of Diatomite-Mediated Growth and Stress Modulation in Aerobic Rice under Moisture Stress in Acidic and Alkaline Soils

Global water scarcity poses a major challenge to maintain crop productivity and quality. Silicon has been recognized as a sustainable strategy to mitigate drought-induced stress in plants. Hence, this study aimed to evaluate the potential of diatomite (DE) as a silicon source in alleviating the adverse effects of moisture stress on aerobic rice grown in acidic and alkaline soils. An experiment was conducted with six treatments: 100% field capacity(FC), 100%FC + DE@150kgha⁻¹, 100%FC + DE@300 kgha⁻¹, 50%FC(alone), 50% FC + DE@150 kgha⁻¹ and 50%FC + DE@300 kgha⁻¹. Moisture stress was maintained at 50% FC from 45 to 90 days after sowing (DAS), and leaf samples collected at 90 DAS were analyzed for leaf relative water content(LRWC), electrolyte leakage(EL), proline content and silicon concentration following standard protocols. The plant growth parameters increased with application of DE@300kgha ^-1 at 100%FC in both soils. At 50% FC, DE@300kgha⁻¹ increased LRWC to 44.78% in acidic and 48.93% in alkaline soils. Significant reduction in proline and Electrolyte leakage was recorded with application of DE@300kgha ^-1 and DE@150 kgha ^-1 at 50% FC reaching 31.50 mgg⁻¹ in acidic and 28.82 mg g⁻¹ in alkaline soil and 15.62% and 25.37% EL in acidic and alkaline soils, respectively. Application of DE@300kgha ^-1 at 50% FC significantly increased silicon content in rice straw attaining 4.36% and 4.04% in acidic and alkaline soils, respectively, and with the higher uptake under DE@300kgha⁻¹ in acidic soil (470.92 mgpot⁻¹) and under DE@150 kgha⁻¹ in alkaline soil (169.84 mgpot⁻¹) at 100% FC. Overall, DE@300kgha⁻¹ proved most effective in enhancing aerobic rice performance under moisture stress in both soil types.