Land use impacts on physical properties of 28 years old reclaimed mine soils in Ohio

Reclamation enhances soil quality by improving physical and chemical properties, which helps in restoration of mine soils. Evaluation of the effects of post-reclamation land uses on physical and chemical properties of mine soils helps to identify suitable land uses for mining companies. The objectives of this study were to evaluate the effects of post-reclamation land uses (e.g., forest, hay and pasture) on selected physical properties of soil in relation to undisturbed forest and agricultural land use. Soil samples were collected from the 0- to 5-, 5- to 15- and 15- to 30-cm depths in order to determine particle size distribution, bulk density, water-stable aggregates, mean-weight diameter and soil moisture retention. Cone index and infiltration rate were determined at soil surface. After 28 years of reclamation, bulk density in the surface layer of all land uses in the reclaimed mine soil (RMS) was similar to that of undisturbed forest (1.1 Mg m⁻³) but lower than that of agricultural soils (1.3 Mg m⁻³). However, soil bulk density at lower depths was not affected. The cone index was higher in the RMS-pasture (2.6 MPa) than the RMS-forest (1.4 MPa) and RMS-hay (1.5 MPa) due to the trampling effect of grazing animals. The water-stable aggregates (>2 mm), of 5–8 mm aggregates, were higher in RMS-forest by 24%, 90%, 66%, and under RMS-hay by 13%, 74%, 43% for the 0- to 5-, 5- to 15-, and 15- to 30-cm depths, respectively, than that under undisturbed forest. The mean-weight diameter (0- to 30-cm) of aggregates under RMS-forest and RMS-hay were higher than that under undisturbed forest by 41% and 27%, respectively. The initial infiltration rates at 5 min in RMS under forest, hay and pasture were less by 20%, 53% and 85%, respectively, than that under undisturbed forest (19.3 cm min⁻¹). The reclamation of mine soils with forest and hay improved surface soil bulk density and cone index, and enhanced water infiltration capacity and water-stable aggregates at the lower depths. Therefore, establishment of forest and hay should be encouraged in the RMS.