The Addition of Locally Adapted Microbes Accelerates the Phytostabillization of Mine Soils Amended with a Mixture of Biochar and Biosolids.

The 76-acre Formosa Mine in Southern Oregon has been designated as a USEPA Superfund site. Formosa was added to the USEPA’s National Priorities List because acid mine drainage has severely degraded 18 miles of river and negatively impacted the local steelhead fishery. Although phytostabilization is one pathway to remediate the Formosa site, hostile edaphic conditions are a major impediment to plant establishment. At many mine sites, the microbial-mineral interactions spawn a biogeochemical cycle that perpetuates and increases soil acidity. If the fundamental goal is to establish a permanent ground cover, it will ultimately be important to shift the microbial community structure from one dominated by autotrophs to a community that has a diverse heterotrophic demographic. One strategy to accelerate phytostabilizaization is to engender a major shift in the microbial community by adding locally adapted microbes (LAM) to soil amendments prior to site remediation. The purpose of these studies was to assess feasibility of culturing LAM from forest soils adjacent to the Formosa mine, and inoculating a biochar/biosolid/lime amendment with LAM. The inoculated media was added to mine soil and planted with a native grass. The results of this greenhouse study determined that the addition of LAM did shift the microbial community over four months and demonstrated that biochar/biosolid mixtures provide may propel mine remediation efforts.