Recognizing critical mine spoil health characteristics to design biochars for site improvement to promote stabilizing plant growth
Citation:
Johnson, M. AND J. Novak. Recognizing critical mine spoil health characteristics to design biochars for site improvement to promote stabilizing plant growth. 3rd Asia Pacific Biochar Conference, Gangwon Province, SOUTH KOREA, October 19 - 23, 2016.
Impact/Purpose:
Biochar can be used as an amendment to remediate metal-contaminated mine spoils to grow plants that stabilize the spoil material against wind and water erosion. Additionally, the biochar can immobilize toxic metals which help protect human health and the environment. In this presentation we discuss some approaches we’ve taken for determining which biochar to use for remediating specific mine soils. Since biochar properties depend upon the feedstock from which they are made and the pyrolysis conditions used, we can make biochars to rectify specific spoil deficiencies that could limit plant growth (e.g., low pH, heavy metals, low water holding, and insufficient plant nutrients). Furthermore, we discuss the use of proximally located, undisturbed soils to establish spoil remediation targets. In our work, we have developed a decision-tree flow-chart that identifies salient chemical, physical and microbial characteristics needed for plant growth. Using this combined with our knowledge of site conditions, we can then design a biochar best suited for site-specific remediation. We also propose a framework for monitoring changes in soil conditions and health and plot their progress to gauge their improvement. This research should be of great interest to EPA Remedial Project Managers and others tasked with cleaning up metal-contaminated soils. This abstract is a part of SHC 3.63.
Description:
Biochar can be used as an amendment to remediate metal-contaminated mine spoils for improved site phytostabilization. For successful phytostabilization to occur, biochar amendments must improve mine spoil health with respect to plant rooting plus uptake of water and nutrients. An inappropriate biochar may negatively impact plant growth conditions resulting in poor plant establishment and growth. Matching the appropriate biochar for each mine site requires reconnaissance of spoil chemical and physical conditions and then identifying which properties need rectified to promote plant growth. A rectification hierarchy needs to be established with the primary limiting factor being addressed first, then successive limitations addressed simultaneously or thereafter. We posit that spoils at each site will have a unique chemical, physical, and biological signature that will affect plant growth. For example, some spoils may be extremely acidic, possess phytotoxic concentrations of heavy metals, or have physical conditions that limits water storage and root penetration. Quantifying these and other conditions beforehand allows for the production of designer biochar with specific characteristics tailored for specific plant growth deficiencies within each spoil. Additionally, we recommend the use of proximally located, undisturbed soils to establish spoil remediation targets. In our work, we have developed a decision-tree flow-chart that identifies salient chemical, physical and microbial characteristics needed for plant growth. Combined with our knowledge of site conditions, we can then design a biochar best suited for site-specific remediation. We also propose a framework for monitoring changes in soil conditions and health and plot their progress to gauge their improvement.