Integrated Application of Biochar and Gypsum for the Remediation of Dispersive, Alkaline Sodic Soils
Sodic and alkaline soils impose serious and interacting physicochemical constraints that limit crop productivity. Elevated pH and high exchangeable sodium percentage (ESP) promote clay dispersion, structural degradation, and restricted water movement. While gypsum supplies Ca²⁺ to displace Na⁺, its effectiveness is often limited under high pH conditions, resulting in incomplete reclamation. Biochar can enhance aggregation and hydraulic properties, however, its typically alkaline and may exacerbate pH-driven limitations when applied alone.
This study develops an integrated amendment strategy combining sulfur-modified biochar and gypsum to overcome these limitations. Sulfur modification is designed to reduce biochar alkalinity and introduce controlled pH-regulating functionality, while gypsum enhances Ca²⁺ availability to facilitate Na⁺ displacement, reduce ESP and sodium adsorption ratio, and improve soil chemical balance. Concurrently, biochar contributes to improvements in soil structure, porosity, hydraulic conductivity, water infiltration, and nutrient dynamics. A key innovation lies in engineering biochar reactivity through sulfur incorporation, gypsum integration, and pyrolysis temperature optimisation, enabling systematic control over surface chemistry and amendment performance.
A mechanistic experimental framework will evaluate multiple amendment systems including, sulfur-modified biochar, gypsum-integrated biochar and temperature-optimized biochar in sodic soils using Wheat (Triticum aestivum) and Sorghum (Sorghum bicolor (L.) as test crops. Outcomes will be assessed through changes in pH, electrical conductivity (EC), ESP, SAR, aggregate stability, hydraulic conductivity, and infiltration in soil. This study aims to advance engineered amendment design for sodic soil amelioration. The outcomes will establish a pathway for restoring soil functionality and enhancing crop productivity in sodicity-affected agroecosystems.
Research Training Program Scholarship
