Physico-Chemical Characterization and Mine Soil Genesis in Age Series Coal Mine Overburden Spoil in Chronosequence in a Dry Tropical Environment

Abstract

A pre-requisite to any revegetation plan, as well as restoration of degraded land is the knowledge of physicochemical characterization, which is crucial for prediction of ecological succession for mine overburden spoil, including soil texture, hydrological regimes, pH, organic carbon, nitrogen and extractable phosphorous. Effects of mining activities are markedly adverse, because many of the beneficial soil characteristics may require a long span of time to develop through pedogenic processes, in order to reach the native forest soil condition, which evaluates the degree of functional microbial processes for ecosystem recovery, and used as an index of the progress of soil genesis in mine overburden spoil. Mine spoil samples collected from six different age series overburdens showed progressive increase in clay (%) (r=0.982, p<0.001), water holding capacity and organic carbon, which indicates the development of soil structural stability, aggregation with the increase in age of overburden spoil. The pH of spoil samples was noted to be in acidic range (6.11-6.87). Approximately, 93.7% variability in clay (%) among different mine spoils can be explained due to the variation in organic carbon. The organic carbon, nitrogen and phosphorous content showed an improvement of 2 mg C/g spoil, 161 µg N/g spoil and 8 µg P/g spoil, respectively, over a period of 10 years. Thus, the net annual accumulation rate for carbon, nitrogen and phosphorous on hectare basis amounted to 255 kg C/ha/yr, 20 kg N/ha/ yr and 1 kg P/ha/yr, respectively. Further, it was estimated that the mine overburden spoil to attain the soil features of nearby native forest soil at study site through the process of reclamation, shall take approximately 28 years.

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

“…In this study, the acidity of the spoil soil decreased significantly with the increase in spoil soil age indicating the reduction in AMD due stabilization of sulfide minerals or due to the passive reclamation. Similar results were also reported from spoil soils of Raniganj coal fields [31] and Basundhara colliery [7] in India. Due to rugged hilly terrain with different levels of elevation in the study sites, the exposed acids might have leached down leading to the spatial and temporal decrease in acidity.…”

“…The correlation analysis revealed that a decrease in acidity increased the availability of N and P which in turn helped in the growth of plants, and soil microorganisms. Maharana and Patel [7] also found low N and P in the spoil soils as compared to undisturbed forest soil. Phosphate is an anion and forms strong bonds with particles that generate anion exchange capacity.…”

“…Soil urease and phosphatase were correlated significantly with N and P, respectively, as the two enzymes are involved in N, P cycles . Thus, soil acidity, availability of macronutrients (N, P), toxicity of heavy metals, and metalloids (Ni, Zn, Cu, As), concentration of soil hydrolases (urease, phosphatase), microbial and plant growth showed significant interactions.…”

“…Although there are reports on properties of spoil soils, primarily these have included few parameters only [6,7,[11][12][13]. There are almost no reports on studies incorporating several biotic and abiotic factors on a long-term basis.…”

Individual tree and stand-level carbon and nutrient contents across one rotation of loblolly pine plantations on a reclaimed surface mine

“…Mined land reclamation studies across the world have found that within about a decade following placement, mine soils begin to develop genetic horizons and accumulate organic carbon (Ciolkosz et al 1985;Haering et al 2004;Maharana and Patel 2013). Plant growth media used in mine reclamation may include topsoil and/or overburden (e.g., surface and subsurface materials) given that physical, chemical, and mineralogical properties are deemed suitable (Angel 1973;Daniels and Amos 1985;Hons 1978).…”