Physiological insights into the carbon sequestration potential of vetiver grass in effluent-contaminated soil ecosystems

Vetiver grass is one of the best hyperaccumulator plants, widely used for environmental clean-up, therapeutic, and medicinal purposes. A field experiment was conducted with vetiver grass and organic amendments in tannery effluent-contaminated soils of Erode District, Tamil Nadu. Organic amendments viz., vermicompost (VC), biocompost (BC), and farmyard manure (FYM), were added to the soil in different proportions according to the treatments. Physiological parameters viz., photosynthetic rate, stomatal conductance, and chlorophyll content observed in vetiver grass, recorded 13.53 µmol (CO2), 0.89 mol (H2O), and 38.51%, respectively, in vermicompost amended soil followed by the other treatments. Dry matter production and biomass production were positively correlated with the carbon sequestration potential of vetiver grass. The biomass obtained from the treatment T3 (VC + 100% Soil Test Crop Response (STRC)) recorded the highest carbon dioxide sequestration (33.89 t ha-1). In contrast, the lowest carbon dioxide sequestration (25.42 t ha-1) was recorded in the treatment T1 (Control). Among the various amendments used in the experiment, the soil amended with vermicompost (5 t ha-1) + 50% STCR (T3) performed best regarding crop growth, carbon sequestration, and pollutant removal.