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.