Evaluating Soil Genesis and Reforestation Success on a Surface Coal Mine in Appalachia

Abstract

Surface mining poses a significant threat to the Appalachian region via forest loss and fragmentation. Reclamation methods that utilize heavy grading to prevent landslides and erosion create a compacted landscape that is not suitable for forest establishment or growth. Overburden materials derived from differing geologic strata can exhibit large variation in physical, chemical, and mineralogical properties. Determining which strata should be used for creating a rooting medium for successful reforestation is not well established. Twelve 0.2‐ha plots composed of either segregated brown sandstone, gray sandstone, shale, or a sandstone–shale mixture (four treatments; n = 3) were created on a surface mine in eastern Kentucky using a low‐compaction reclamation method. Each plot was planted with native hardwood tree seedlings following the Forestry Reclamation Approach. After two growing seasons, brown sandstone treatments had four times greater extractable P (Mehlich III) and five times greater total N than the other treatments. This helped contribute to greater tree growth on brown sandstone treatments. Spoil settling was faster in the shale treatments due to the loss of carbonate cements. Clay contents and 2:1 minerals were also greater in the whole soil of the shale treatments, leading to greater plant‐available water and a greater cation exchange capacity. Gray sandstone treatments exhibited alkaline conditions (pH = 8.8) that suppressed tree growth. The mixing of brown sandstone and shale overburdens may produce a suitable combination of higher fertility, water holding capacity, and faster settling in reclaimed mine environments.