Carbon Sequestration Potential in Soils Reclaimed with Municipal Biosolids and Other Residuals.

Increasing soil carbon reserves  by increasing  organic and inorganic carbon concentrations in degraded  or mined soils  and returning them to productivity has been proposed as a means to sequester carbon and increase carbon reserves (Lal et al., 1998; Akala and Lal, 2001; Lal et al., 2003). Carbon reserves are increased on an annual basis through build up of soil carbon and above ground biomass.  Different annual accrual rates have been proposed for different soil types, climates and ecosystems.  In each case, these estimates have been prepared without consideration of the potential for use of organic soil amendments to both accelerate the carbon accumulation process and potentially result in increased soil carbon concentrations.  There is a long-standing practice in parts of the United States to use high carbon residuals, primarily municipal biosolids, for restoration of coal mines and gravel pits.  Resent research has demonstrated that this approach is also effective for hard rock mining sites.  Combining the use of organic amendments with traditional restoration practices has the potential to both restore a vegetative cover to sites more quickly as well as to restore carbon reserves.  As costs of using residuals is often subsidized by the generator and there is a potential market for sequestered carbon, this approach offers a cost effective option to restoration with use of commercial fertilizers.