Physical and Chemical Properties of a Minespoil Eight Years after Reclamation in Northeastern Ohio

The potential of using flue gas desulfurization by-products (FGD) for the reclamation of acid minespoil was assessed in Tuscarawas County of Ohio, USA. In Treatment 1, 280 Mg ha⁻¹ of FGD was incorporated into the graded spoil to a depth of 20 cm. In Treatment 2, 280 Mg ha⁻¹ of FGD and 112 Mg ha⁻¹ of yard waste compost were incorporated into the graded spoil (FGDC). In Treatment 3, 112 Mg ha⁻¹ of limestone was incorporated into the graded spoil and was covered with 20 cm of graded borrowed topsoil (BTS). Six cores and six bulk soil samples were obtained from each treatment for the 0- to 10-cm depth in summer 2002. From the 10- to 20-cm depth, only bulk soil samples were obtained. Bulk and core soil samples were also collected from an unreclaimed spoil (SP) and a nearby unmined soil (UMS). Among the three reclamation treatments, BTS showed better soil quality with higher soil organic C (28.5 Mg ha⁻¹), water-stable aggregation (556 g kg⁻¹), and mean weight diameter (3.2 mm) of aggregates than FGDC or FGD treatments. The FGDC had higher soil inorganic and organic C than FGD. However, saturated hydraulic conductivity (K ₛ), cumulative infiltration (I), infiltration rates at 5 min (i ₅) and 2.5 h (i c), and soil pH were similar among three treatments. Among treatments and controls, soil bulk density (ρb) was lower for FGD, FGDC, and UMS than BTS and SP; and water-stable aggregation and mean weight diameter of the aggregates was higher for UMS and BTS than FGDC, FGD, and SP for both depths. The I and i c were similar among UMS and treatments. Reclamation improved the soil quality with higher soil pH (≈7) and inorganic and soil organic C than in the SP. With respect to FGD, the soil organic C in FGDC increased at the rate of 0.64 Mg ha⁻¹ yr⁻¹ for the 0- to 10-cm depth. Overall, BTS was the best reclamation treatment. However, if topsoil is unavailable or transport is expensive, FGDC can be used as an effective reclamation material.