Soil organic carbon pools and sequestration rates in reclaimed minesoils in Ohio.

A chronosequence of reclaimed minelands under two land uses was studied to determine the potential of minesoil reclamation to sequester carbon (C). Effects of four treatments, consisting of pasture and forest with and without topsoil application, were assessed on temporal changes in soil C pool. The control sites were a 70-yr-old marginal agricultural land under pasture and a 65-yr-old reclaimed forest land. The soil organic carbon (SOC) pool of pasture treatment with topsoil application increased from 9.2 to 55.4 Mg ha(-1) after 25 yr for the 0- to 15-cm depth and from 7.8 to 37.8 Mg ha(-1) for the 15- to 30-cm depth. The rate of SOC sequestration in the pasture treatment ranged from 0.5 to 3.1 Mg ha(-1) yr(-1) for the 0- to 15-cm depth, and from 0.4 to 1.9 Mg ha(-1) yr(-1) for the 15- to 30-cm depth over the 25-yr period. The SOC pool of forest treatment with topsoil application increased from 14 to 48.4 Mg ha(-1) in 21 yr for the 0- to 15-cm depth, and from 8.4 to 14.5 Mg ha(-1) for the 15- to 30-cm depth. The rate of SOC sequestration in the forest treatment ranged from 0.7 to 2.3 Mg ha(-1) yr(-1) for the 0- to 15-cm depth and from 0.3 to 0.4 Mg ha(-1) yr(-1) for the 15- to 30-cm depth over the 21-yr period. The pasture and forest treatments without topsoil application were a minimum of 30 yr old and hence, the SOC pools were almost constant ranging between 60 and 70 Mg ha(-1) for the 0- to 15-cm depth and 30 and 40 Mg ha(-1) for the 15- to 30-cm depth.