Quality of Soil Carbon Sequestered
The average EET: EBz ratios increased significantly (p< 0.05) along the chronosequence following the order Gmelina arborea > Azadirachta indica > Dalbergia sissoo (Table-7) . The average EET: EBz ratios were higher atGmelina arborea in both reclamation years. Average E4: E6 ratios of HAs decreased along the chronosequence for all three tree species.
The FT-IR spectra are capable of identifying the major functional groups and broad classes of biomolecules present in the SOM, such as carbohydrates, lignins, cellulose, and amino acids, through the vibrational characteristics of their structural bonds. In the present study, the FT-IR spectral methods were mainly intended to improve the overall understanding of the SOC molecular characteristics in the mine soils. Also, the FT-IR method was used to estimate the “relative abundances” of broad classes of functional groups in the mine soils rather than to quantify the absolute of their amounts. The FT-IR spectral patterns identified following absorption bands in the mine soils (Figure 4), namely broadband between 2983 and 3000 cm–1, corresponding to CH3, CH2, and NH3 stretch; a peak at 1862–1820 cm–1 arising from C=O stretching of cyclic anhydrides and mixed anhydrides; peaks at > 3400 cm–1 corresponding to O-H and N-H stretch; and a peak at 1695 cm–1 for COOH vibrations; a peak at 1500-1490 cm–1representing aromatic carbonyl group;873-728 cm–1 corresponds to aromatic C-H group and peak around 1500 cm–1 represents N-H, C=N(amide II band), and C=C.
The FT-IR spectral patterns appeared similar for the mine soils (Figure 5). Relative absorbance intensities of certain bands differed between the mine soils (Figure 5). For example, in the case of Azadirachta indica, Dalbergia sissoo and Gmelina arborea relative proportions of aromatic groups along the chronosequence increased(Figure 5(a, b, c)). In case of Dalbergia sissoo and Gmelina arborea COO -, -C-NO2, C=C, and aromatic C-H group were highest in 25years old reclaimed soil than in 8 years old reclaimed soil.