Development of Technosol properties and recovery of carbon stock after 16 years of revegetation on coal mine degraded lands, India

Abstract

Surface mining is recognized as one of the essential anthropogenic activities which drastically disturbs the ecosystem. To offset the impacts of surface mining, revegetation is widely used to restore the disturbed landscape. The present field study was carried out to assess the status of an ecosystem structure, soil quality and C pool of the 16-years old revegetated post-mining site and compared to an undisturbed forest site. For this, physicochemical, biological and hydrological properties of Technosols were analyzed, and differences in these parameters were quantified. Vertical distribution of soil nutrients (NPK), soil organic carbon (SOC) and soil inorganic carbon (SIC) were assessed in the upper 100 cm (at an interval of 20 cm) of Technosols and forest soils. After 16-years of revegetation, autochthonous tree species comprise 17% of the total tree population on the reclaimed site. Technosol quality was increased in terms of accumulation of SOC, available nitrogen (N), and available phosphorus (P). SOC and total N stock recovered in Technosols were 70% and 47% of the reference forest soils, respectively. Likewise, after 16-years of revegetation, ecosystem C pool was 33% of the undisturbed forest site. Increase in C pool can be attributed to the development of plant biomass C, accretion of SOC and litter C pool. The study provides an insight into the magnitude of nutrient content and development of ecosystem C pool in a reconstructed ecosystem and importance of revegetation of post-mining sites to offset CO2 emission. The study concluded that plantation of multipurpose tree (MPT) species will improves Technosol quality, facilitates natural colonization of native tree species and increases ecosystem C pool along the age of revegetation.