Effect of Fabricated Soil Application On Soil Biological and Chemical Properties

1. Effect of Fabricated Soil Application On Soil Biological and Chemical Properties P. Badger1, K. Conley1, V. Kefeli2, M. Kalevitch1, W. Dress1, K. Leo1, J. Sabol1, and L. Zawlesky1 1 Robert Morris University 2 BioMost Inc. Soil Metal Concentration Abstract Fabricated soil was created five years ago for the rehabilitation of abandoned mining soil.  Soil samples were obtained from different locations named by the presence of certain trees grown on these specific plots. Microbial composition of FS consisted of fungi imperfecti and various bacterial species. In the first few years the predominant bacterial species were fermenting and non-fermenting gram-negative bacillus, Bacillus spp., Actinomycete, and Micrococcus spp. Several new forms of microorganisms were found lately- Sphingomonas, Chryzeobacterium and Rhizobium that were not present in earlier years. Finally, the bacterial content on FS was 100 times higher, than of the mining soil which was a subject of the landscape rehabilitation. Soils were also analyzed for metal and nutrient content.  The addition of FS added significant organic matter to soil.  FS had > 15% OM compared to < 10% for mining soil.  Cation exchange capacity varied from 8.5 to 48.0 cmolc/kg. Mining soils contained high levels of some metals, including Zn (> 1300 mg/kg soil), Fe (> 1500 mg/kg soil) and Ni (> 900 mg/kg soil).  Soil Metal Concentration (mg/kg soil) Soil Metal Concentration (mg/kg soil) * * Soil concentrations of Ca, Co, Mg, Ni, and Zn were significantly greater in soils amended with fabricated soil compared to mining soil. Concentrations of most elements were lower than reference data from Allegheny county A horizon soils from the USGS PLUTO database (USGS 2001). Soil Properties Soil Microbial Composition Study Site Results are presented for pooled samples collected from mining soil and mining soil amended with fabricated soil. The fabricated soil amendment included a variety of organic sources (compost, mulch, etc.). Soils were digested following EPA method 3050B and analyzed by AA spectroscopy. Organic matter was measured by loss on ignition. Soil data was compared to reference data for soils in the USGS PLUTO database (USGS 2001). All reference data from the PLUTO database were from Allegheny county A horizon soils. Organic matter, Total N, and P and cation exchange capacity were greater in soils amended with fabricated soil. Soil pH was also significantly greater in soils amended with fabricated soil. Total K was similar between both soils. Bacterial concentration from fabricated soil plots was over 100 fold greater than mining soil with no amendment. Bacterial composition of mining soil plots was species poor – dominated by Bacillus spp. and Actinomycetes. Plots amended with fabricated soils have shown increased microbial growth and species composition . Literature Cited U.S. Geological Survey, 2001, Geochemistry of soils in the US from the PLUTO database: U.S. Geological Survey, Reston, VA.