| Summary: | Natural soils in the Appalachian coal mining region occur on steep slopes and are often thin, rocky, acidic, and/or infertile. This often makes use of natural topsoil for surface coal mine reclamation impractical. Sandstone (SS) and siltstone (SiS) topsoil substitute materials in mixed and pure treatments were compared to ascertain their effects on soil genesis and tall fescue (Festuca arundinaceae Schrab.) growth in a rock mix study. A second surface amendment experiment with similar objectives was established and contained treatments of sawdust, topsoil, a control, and four rates of sewage sludge.
Soil pH, extractable P, and coarse fragment contents decreased at the soil surface from 1982 to 1984. The CEC decreased from 1982 to 1983 due to leaching of cations solubilized from carbonates, but stabilized by 1984. Soil total-N and water availability increased from 1982 to 1984.
Particle size distributions changed as sand and >2 mm sized materials weathered into silt and clay sized particles. As sand contents decreased over time, silt contents increased. Morphologically distinct A horizons developed in these soils rapidly and were formed primarily by plant rooting and organic matter additions. Treatment application, topsoil substitute placement, and grading also created morphologically distinct horizons.
Fescue biomass production indicates topsoil substitutes support more vigorous vegetative growth than topsoil, especially when topsoils are mixtures of subsoil and A horizons. Biomass production was primarily limited by N, P, and water availability. Blended rock mixes consistently supported higher biomass production than pure SS and SiS treatments. Municipal sewage sludge applied at rates-56 Mg/ha equaled or exceeded inorganic fertilization for establishment and maintenance of tall fescue stands, and did not cause heavy metal phytotoxicity. === M.S.
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