Carbon mineralization in a Semi-evergreen forest of Northeast India: Role of soil physico-chemical and mineralogical properties

Abstract

Decomposition of soil organic carbon is significantly influenced by soil physico-chemical, biological, and mineralogical properties. Thus, they play crucial role in regulating soil CO₂ efflux. This study investigated carbon mineralization within three natural ecosystems (grassland, forestland, wetland) situated in Kaziranga National Park of Northeast India. Over two years, soil samples were methodically collected across pre-monsoon, monsoon, and post-monsoon seasons. Grassland and forestland soils were collected at 0–15 cm and 15–30 cm depths. Thorough analyses were conducted on soil physicochemical, and mineralogical properties. Soil carbon mineralization was estimated to enhance our understanding of the interplay between environmental conditions, SOC stocks, and soil properties, facilitating the prediction of ecosystem CO₂ efflux. The study revealed significant correlations between soil physico-chemical and mineralogical properties and carbon mineralization within the studied ecosystems of Kaziranga National Park. Soil moisture was identified as the primary regulator of soil carbon mineralization, with soil texture playing a minor role. Soil chemical parameters, such as SOC and total N governed carbon dynamics, while soil pH consistently showed a negative correlation with carbon mineralization. Mineralogical analysis revealed the presence of phyllosilicate minerals and organic matter. Despite diverse soil mineral composition, no significant influence on carbon dynamics in KNP was observed. However, further comprehensive field-based assessments of carbon mineralization are required to complement the preliminary findings obtained through lab-based incubation studies. This will be required to evaluate the resilience of soil carbon stocks and thus to predict future changes in soil CO₂ efflux in this ecologically significant region of Northeast India.