CARBON DYNAMICS OF RECLAIMED COAL MINE SOIL: A CHRONOSEQUENCE STUDY IN THE GEVRA MINING AREA, KORBA, CHHATTISGARH, INDIA

Abstract

Reclamation of mined soil improved soil quality and SOC sequestration. A chronosequence study consisting of 8 and 25years old reclaimed mine soils under Azadirachta indica, Gmelina arborea, Dalbergia sissoo and recently dumped soils in Gevra, Chhattisgarh, India was initiated to quantify the quality and quantity of carbon pools. MBC (microbial biomass carbon) showed highest value in case of Azadirachta indica (1468.45 ug C/g soil) followed by Dalbergia sissoo (1338.19 ug C/g soil) and Gmelina arborea (1160.61ug C/g soil) in surface soil after 25years of reclamation. Mean total soil C stock was estimated as 334.72,226.94 and 191.20 Mg C ha-1, under Azadirachta indicia, Dalbergia sissoo and Gmelina arborea plantation respectively. Carbon stock of the soil increased with an increase in year of reclamation. Among the four different pools of organic carbon, the carbon per cent was highest in the non-labile pool of carbon under Azadirachta indica (88.25%). Humic acid C content and C/N ratio had increased under Azadirachta indica, Dalbergia sissoo with an increase in the year of reclamation. FT-IR spectra in the case of Azadirachta indica, Dalbergia sissoo and Gmelina arborea indicated that relative proportions of aromatic groups along the chronosequence have increased. TOC (Total organic carbon) content was highest under Azardichta indica but aromaticity was highest under Gmelina arborea as obtained by E4/E6 and EET: EBZ ratio. These results indicated that different carbon pool and aromaticity of carbon improved with the increase in year of reclamation and significant relationships were present between spectroscopic indices and different soil carbon parameters.