Land Management Effects on Carbon Sequestration and Soil Properties in Reclaimed Farmland of Eastern Ohio, USA

Reclaimed mined soils (RMSs) could restore soil quality and ecosystem productivity while sequestering C and off-setting some of C emissions associated with coal utilization. The study was conducted to evaluate the effects of tillage and pasture management on soil physical properties, soil organic carbon (SOC) and microbial biomass carbon (MBC) in RMSs managed for agricultural use in eastern Ohio. Soil bulk density (ρb) of the top 50 cm ranged from 1.11 to 1.93 Mg·m. The ρb of the RMSs was significantly more than that of the undisturbed soils. Water stable aggregates (WSA) and mean weight diameter (MWD) of the 0 10 cm soil layer were significantly lower under reclaimed conventional tillage (RCT) than reclaimed no tillage (RNT) and reclaimed pasture (RP), probably due to tillage-induced disturbance. The SOC pool of the top 50 cm layer was 64.2, 66.5, 75.4, 86.1 and 101.1 Mg·C·ha for undisturbed pasture (Und P), RNT, RCT, RP and undisturbed hardwood forest (Und HWF), respectively (LSD = 7.7 Mg·ha). The RMSs under pasture accumulated SOC at higher rates than RMSs under cropland. Reclaimed pasture land use increased SOC pool by 14% or 0.5 Mg·ha·yr and 30% or 0.9 Mg·ha·yr relative to RNT and RCT land uses, respectively. Our data indicated that RMSs under forest and pastures had higher SOC sequestration rates than RMSs under arable land use, probably due to disturbances associated with farm operations. The MBC of the RMSs were generally lower than those of the undisturbed sites. The disturbances associated with mining and reclamation reduced the MBC by 39%, 53% and 21% under RCT, RNT and RP compared to the undisturbed forest and pasture sites. However, the amount of mineralizable C was not significantly different among land disturbances or land uses.