Carbon Storage and Minesoil Properties in Relation to Topsoil Application Techniques

Reclaimed minelands could act as C sinks, but shallow soil, nutrient deficiency, and compaction could limit C accretion in these ecosystems. This study evaluated the impact of topsoil application techniques on total C storage (tree biomass and soil organic C [SOC]) in 15‐yr‐old experimental plots established on reclaimed land in southeastern Ohio. Treatments included topsoil (graded overburden [OV] and standard [ST] and ripped topsoil [RT]) and P fertilization (0 and 2.24 Mg ha −1 of rock phosphate). One half of each plot was planted with Austrian pine ( Pinus nigra J.F. Arnold ssp. nigra ) and the other half with green ash ( Fraxinus pennsylvanica Marshall). A significant effect of topsoil application on tree growth and SOC was noted. In green ash plots, aboveground biomass was always <3.4 Mg C ha −1 , but in Austrian pine stands it averaged 10.3, 15.2, and 2.1 Mg C ha −1 in the ST, RT, and OV plots, respectively. The pool of recent SOC (after discounting geogenic C) was in the order: ST (34.9 Mg C ha −1 ) > RT (29.8 Mg C ha −1 ) > OV (17.8 Mg C ha −1 ). The lower SOC in RT than in ST plots was attributed to enhanced C mineralization by soil ripping, but with the fast‐growing Austrian pine, this SOC deficit was compensated by a greater (by 4.9 Mg C ha −1 ) standing tree biomass in the RT plots, resulting in comparable total C storage with either ST or CT. With the slow‐growing green ash, however, total C storage was significantly lower in RT (27.9 Mg C ha −1 ) than in ST (37.4 Mg C ha −1 ) plots. Thus, the impact of topsoil application technique on C storage in these aggrading ecosystems is largely determined by tree growth and productivity.