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Long‐term Effects of Rock Type on Appalachian Coal Mine Soil Properties
Author(s) -
Nash Whitney L.,
Daniels W. Lee,
Haering Kathryn C.,
Burger James A.,
Zipper Carl E.
Publication year - 2016
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2015.10.0540
Subject(s) - topsoil , weathering , soil water , geology , parent material , siltstone , soil science , overburden , organic matter , clay minerals , mineralogy , geochemistry , chemistry , mining engineering , facies , geomorphology , organic chemistry , structural basin
Rock‐derived overburden material is used as a topsoil substitute for reclamation of Appalachian coal mines. We evaluated five mixtures ( n = 4 each) of sandstone (SS) and siltstone (SiS) overburden as topsoil substitutes for 25+ years to quantify changes in mine soil properties. The study area was planted only to tall fescue [ Schedonorus arundinaceus (Schreb.)], but over 50 herbaceous species invaded over time. Standing biomass was highest in early years (5.2–9.3 Mg ha −1 in 1983) and was strongly affected by rock type (SS > SiS), declined significantly by 1989 (1.5–2.4 Mg ha −1 ), and then increased again (2×) by 2008. However, there was no long‐term rock type effect on standing biomass. Rock fragments and texture differed after 26 yr, with fewer rock fragments in the SS‐dominated mixtures (53 vs. 77% in SiS) and lower sand and higher clay in the SiS‐dominated mixtures. Soil pH initially ranged from 5.45 (SS) to 7.45 (SiS), dropped for several years, increased in all SiS mixes, and then slowly declined again to 5.65 (SS) to 6.46 (SiS) over the final 15 yr. Total N, organic matter, and cation exchange capacity increased with time, and extractable P decreased. Chemical weathering was most apparent initially, but physical weathering of rock fragments and changes in texture continued throughout the study period. Influences of original rock mixtures remained apparent after 25+ yr in both physical and chemical properties of these mine soils, which remained much coarser than local native soils but were higher in pH, exchangeable cations, and extractable P. Core Ideas Coal mine overburden rock type controls initial and long‐term mine soil properties. Rock fragments significantly decreased and silt+clay increased over 25+ years. Mine soil pH quickly decreased, increased, and then decreased again over time. Mine soil CEC increased dramatically over time, primarily via humus accumulation. Rock type affected short‐term standing biomass but not over the long‐term.