Iron mining activities disrupt the original landscape resulting huge mine spoil dumped in the form of overburden, which alter ecosystem function. Monitoring of mine spoil is pre-requisite to predict soil quality with appreciable potential in contributing towards sustainable soil management. The study addressed the assessment of enzyme activities that reflect soil quality with concomitant ecosystem functioning and provide empirical evidences in support of mine spoil genesis explaining the variability in microbial community composition among different age series mine overburden spoil over time. The study represents holistic approach using quantitative biomarkers such as enzyme activities (amylase, invertase, protease, urease and dehydrogenase) and their kinetic parameters (Vmax, Km and Vmax/Km), which established linkages between the fluxes driving nutrient pool for its worth in sustainable soil management. Comparative assessment revealed gradual improvement in enzyme activities from fresh mine spoil to 25yr old mine spoil. The study indicated consistent increase in Vmax with concomitant decrease in Km with increase in age of mine spoil reflecting mine spoil genesis. The shift in Vmax/Km revealed the variation in microbial community composition with changes in enzyme activities. Stepwise multiple regression analysis was performed to quantify the contribution of physico-chemical properties influencing enzyme activities. Principal component analysis can able to discriminate seven different mine spoil and NF soil into independent clusters based on their enzyme activities and kinetic parameters. The study clearly revealed that enzyme activities and kinetic parameters can be considered as soil quality descriptors for the assessment of mine spoil genesis promoting the progress of restoration.
