Seasonal and Temporal Dynamics of Physicochemical and Biological Properties of Chronosequence Coal Mine Spoil Soils

Open cast coal mining cause severe damage to soil physicochemical and biological properties. The present study, therefore, was carried out to evaluate the effect of open cast coal mining on the seasonal and temporal dynamics of soil properties. Soil samples were collected from chronosequence spoil soils and one undisturbed forest in two seasons for 2 consecutive years. Most of the studied soil properties deviated from the forest soil. The dumping soils were highly acidic as compared to the forest soil. Soil acidity decreased with increase in soil age. Significant negative correlation of soil pH and nickel (Ni), zinc (Zn), copper (Cu), nitrogen (N), phosphorus (P) (p < 0.01), indicated that increase in spoil soil acidity increased the solubility/availability of these heavy metals, while decrease in soil acidity increased the availability of N and P. High soil acidity and higher concentration of heavy metals reduced the bacterial population number and activity of soil enzymes. Soil enzymes and bacterial population number significantly correlated with each other indicating their interdependence. Seasonal dynamics was observed in soil temperature. While, temporal dynamics was exhibited by soil pH, N, P, Ni, Zn, Cu, and dehydrogenase activity. Soil moisture content, arsenic, bacterial population number, urease, and phosphatase activity exhibited both seasonal and temporal dynamics. Ordination diagram of principal component analysis showed strong relationship of soil biological properties with undisturbed forest and heavy metals with disturbed spoil soils.