Comparison Between Minesoils Reclaimed to Pasture and Managed Pastures in the Appalachian Region: Required Number of Samples to Characterize Carbon Stock.

Carbon sequestration estimation is based upon the determination of soil carbon stock which requires precise characterization of soil bulk density. This study was aimed at comparing the minimum number of soil samples required to characterize surface 0-6 cm bulk density under two contrasting soil conditions: a reclaimed minesite and a native soil, both under grassland landuse located in Monongalia and Preston County, West Virginia. Sampling at the minesite was performed with an auger sampler using a modified excavation method while that at the native soil was done using an Uhland sampler. The sites were characterized by similar landscape patterns: both located at summit and upper backslope positions having an approximate area of 2 hectares. Both sites were sampled following an irregular grid with 74 and 180 samples being collected from the reclaimed minesite and native grassland respectively. Soil bulk densities were reported on gravel-corrected basis.

Average soil bulk density at the reclaimed minesite was 1.47±0.30 g/c.c. with 20.40% coefficient of variation while that at the native grassland site was 1.18±0.01 g/c.c. and 8.13% respectively. The estimated minimum number of samples required to characterize soil bulk density at the reclaimed minesite was several orders of magnitude higher than that of the native grassland. This study indicates that characterization of soil bulk density in disturbed soils such as reclaimed minelands would require a higher number of samples as compared to native undisturbed ecosystems making the determination of carbon stocks, and hence carbon sequestration rates, difficult in these disturbed soils.