You are here:
Biochar Improves Performance of Plants for Mine Soil Revegetation
Citation:
Olszyk, D., T. Shiroyama, M. Bollman, V. Manning, K. Trippe, J. Novak, D. Watts, AND M. G. Johnson. Biochar Improves Performance of Plants for Mine Soil Revegetation. Pacific Northwest Chapter meeting of the Society of Environmental Toxicology and Chemistry, Corvallis, OR, March 08 - 10, 2018.
Impact/Purpose:
Within the US there are thousands of abandoned hardrock mines, of which only a fraction have been remediated or contained. Often simple steps such as establishment of plant cover could reduce wind and water erosion of contaminated waste materials and the contamination of downslope receiving waters. Biochar (the solid by-product of pyrolysis of biomass), has the potential to improve plant performance for revegetation of mine soils by improving soil chemistry, fertility, moisture holding capacity and by binding heavy metals. We investigated the effect of gasified conifer softwood waste biochar to improve the growth of two candidate plant species for mine soil revegetation: wild blue rye grass (Elymus glaucus) grown from seed, and Douglas fir seedlings (Pseudotsuga menziesii). Plants were grown in the low pH mine spoil soil with a variety of amendments. Preliminary results indicate that addition of 1% lime (by weight) was required to raise the pH of the soil enough to allow for plant growth, with biochar causing a slight additional increase in pH. Biosolids (2% by weight) were added to supply nutrients, but resulted in phytotoxicity due to excess N Biochar (1, 2.5 or 5% by weight) in addition to lime and biosolids, enhanced plant growth, especially for wild blue rye, with increased growth as biochar amendments increased. Biochar likely reduced the concentration of plant nutrients to below plant phytotoxic levels. The interaction of soil inoculation with Locally Effective Microbes (LEM) and rate of biochar amendment also was evaluated for growth of Douglas fir. Overall the study suggested that addition of biochar in combination with other appropriate soil amendments will enhance plant growth for revegetation purposes for low pH metal-contaminated mine soils. This Abstract contributes to SHC 3.62.2.
Description:
Biochar (the solid by-product of pyrolysis of biomass), has the potential to improve plant performance for revegetation of mine soils by improving soil chemistry, fertility, moisture holding capacity and by binding heavy metals. We investigated the effect of gasified conifer softwood waste biochar to improve the growth of wild blue rye (Elymus glaucus) and Douglas fir (Pseudotsuga menziesii) seedlings growing in a low pH mine spoil soil with a variety of amendments. Preliminary results indicate that addition of 1% lime (by weight) was required to raise the pH of the soil enough to allow for plant growth, with biochar causing a slight additional increase in pH. Biosolids (2% by weight) were added to supply nutrients, but resulted in phytotoxicity due to excess N. Biochar (1, 2.5 or 5% by weight) in addition to lime and biosolids, enhanced plant growth, especially for wild blue rye, with increased growth as biochar amendments increased. Biochar likely reduced the concentration of plant nutrients to below plant phytotoxic levels. The interaction of soil inoculation with Locally Effective Microbes (LEM) and rate of biochar amendment also was evaluated for Douglas fir. Overall the study suggested that addition of biochar in combination with other appropriate soil amendments will enhance plant growth for revegetation purposes low pH metal-contaminated mine soils.