| Abstrakt: |
To provide recommendations for establishment of plants on low‐pH Formosa Mine tailings, two greenhouse experiments were conducted to evaluate the use of remedial amendments to improve the survival and growth of Douglas fir (Pseudotsuga menziesii) seedlings. A preliminary experiment indicated that 1% lime (by weight) raised tailings pH, permitting seedling survival. However, high rates of biosolid application (BS; 2% by weight) added to supply nutrients were phytotoxic when added with lime. A gasified conifer biochar (BC) added to tailings at 1%, 2.5%, or 5% (by weight), along with lime and BS, caused an additional increase in pH, decreased electrical conductivity (EC), and tended to increase the survival of Douglas fir. The addition of a locally sourced microbial inoculum (LSM) did not affect survival. A subsequent experiment expanded our experimental design by testing multiple levels of amendments that included lime (0.5% and 1% by weight), three application rates (0.2%, 0.5%, and 2%) of two nutrient sources (BS or mineral fertilizer), BC (0% and 2.5%), and with or without LSM. There were many interactions among amendments. In general, Douglas fir survival was enhanced when lime and BC were added. These experiments suggest that amending with lime, a nutrient source, and BC would enhance revegetation on low‐pH, metal‐contaminated mine tailings. Core Ideas: Amendments influenced Formosa Mine tailings chemistry and affected survival of Douglas fir in greenhouse studies.Lime decreased tailings leachate heavy metal availability, and increased pH and plant survival.Biosolids (BS) or fertilizer (F) provided plant nutrients, but 2% by weight resulted in phytotoxicity.Biochar (BC) enhanced plant survival likely by further increasing tailings pH.Amending with 1% lime, 0.25% or 0.5% BS or F, and 2.5% BC is recommended to establish plants on mine tailings. [ABSTRACT FROM AUTHOR] |
