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Acidic/Heavy Metal-Tolerant Plant Cultivars Demonstration, Anaconda Smelter Superfund Site
Primary Issue Addressed: Sustainability
Secondary Issues Addressed: Source Control, Characterization
Project Site: Research has been performed (over the past 10 years) at various locations within and adjacent to the Anaconda Smelter Superfund site. The present focus is the Moto-X site located in the Lost Creek drainage, north of Anaconda, Montana.
Collaborating Entities: MSE, Deer Lodge Valley Conservation District (DLVCD) and U.S. Department of Agriculture/Natural Resources Conservation Service Bridger Plant Materials Center (BPMC)
Cost Share: In-kind services (facilities and labor) provided by the collaborating entities; partial funding under the Montana Department of Justice’s Clark Fork Restoration Fund Grant Program (2000-2004).
Project Description
Presently, grass, forb, and shrub species commercially available for reclaiming acidic/heavy metals-contaminated (A/M) soils often come from outside the Northern Rocky Mountain region. These cultivated varieties may not tolerate the climatic-edaphic stresses (in addition to A/M pollution stresses) as well as would the A/M-tolerant ecotypes indigenous to the region. Over the past decade, plant populations exhibiting A/M tolerance potential have been collected from the Anaconda Smelter Superfund Site and evaluated in laboratory, greenhouse, and field trial studies. The results to date indicate that self-sustaining plant communities comprised of native A/M tolerant ecotypes are possible. Thus, the long-term goal of this project is to formally compare the performance of local seed mixtures against comparable mixes now commercially available. If the local ecotypes (of the particular grass/forb species) are indeed best performing, they would be made available for numerous full-scale reclamation of hard-rock mine/mill/smelter sites in the region.
Status
The following activities occurred in fiscal 2005: collection and laboratory analysis of plant and soil samples from the Anaconda area; field evaluations of plant performance; and production of seeds (at the Bridger Plant Materials Center) from the most promising grass/forb accessions. Although there has been some mortality, the top performers of the 2003 and 2004 growing seasons continue to demonstrate their ability to withstand the harsh soil conditions at the Moto-X site. A local accession (9081620) of slender wheatgrass is the top performer, having average canopy cover and biomass production values of 75% and 0.82 kg dry leaf and stalk biomass (LSB), respectively. These results exceed the original project objectives of 30% to 50% and 0.1 to 0.2 kg/m2 LSB, respectively. Other local accessions that met these performance criteria–whereas their cultivated counterparts did not–include another slender wheatgrass (9081621) and big bluegrass (9081633). All three local accessions also met the project’s plant vigor and heavy metals uptake criteria.
During the previous growing seasons, the only forb/shrub species showing significant (9.5 seedlings/ft2) emergence was winterfat Open Range Germplasm. However, after the 2005 season, the following additional plants were observed: indigenous silverleaf phacelia (9081632), Old Works fuzzytongue penstemon, Richfield firecracker penstemon, and Northern Cold Desert winterfat. The surviving plants of Open Range winterfat and the phacelia (above) exhibited good vigor, growth, and seed production.
In the seed mixture trials, the experimental mixes that contained native
local source materials were far superior to the developed mixes that consisted
of native nonlocal source (upland mix) and introduced cultivars (waste
management areas). However, it was estimated that the majority of plants
in the experimental mixtures, both upland and waste management areas,
continue to be 9081620 slender wheatgrass, which was the best overall
performer on this particular site.
The tissue analyses show that the heavy metal concentrations in
and on the plant tissue sampled from the Stucky Ridge plots were
generally within the tolerable limits for consumption by domestic
livestock and wildlife.
The overall performance on the Stucky Ridge plots was quite variable, with strips running north and south that had poorer plant vigor and biomass production. The Pryor slender wheatgrass strips between replications (running east and west) exhibited waves of good and poor establishment and performance. Soil samples (0–6 in.) were taken under four plant stands of slender wheatgrass ranging from excellent to very poor in hopes of explaining this variability. It was thought that the incorporation of the amendments may have created strips with varying pH. Soil analysis for pH indicated no difference in pH (all 6.8 to 7.3) under the varying stand of slender wheatgrass. Therefore, this variability is still unexplained.
A/M-tolerant Washoe Germplasm basin wildrye (Figure 2a), Prospector’s Germplasm common snowberry, and Source-Identified Old Works Germplasm fuzzytongue penstemon have been released by the BPMC. Seed from the wildrye has been distributed to two commercial growers in Montana, while penstemon seed has been distributed to one grower each in Washington and Idaho. No growers have yet shown interest in production of the snowberry.
A final project report will be released (under the Mine Waste Technology Program) in late spring 2006. Approximately $245K was awarded by the State of Montana to the DLVCD/BPMC in December 2004 to continue development of A/M-tolerant releases through 2008.
During the winter of 2006, Copperhead Selected class germplasm slender wheatgrass (9081620), shown in Figure 2b, will be submitted for release consideration to the Variety Release committee at Montana State University and to the Pure Seed Committee at the University of Wyoming. If the release is successful, G1 seed will be made available to commercial growers in the spring of 2006. Plant materials that are being considered for release in 2007 are silverleaf phacelia (9081632) and big bluegrass (9081633). Other potential releases within the next 3 years include western wheatgrass (9081968), bluebunch wheatgrass (9081636), and Wood’s rose (9081638).
Figure 4a. The USDA's Bridger
Plant Materials Center released Foundation class Washoe germplasm
basin wild rye. (Leymus cinereus is shown in photo.)
Figure 4b. The Bridger Plant Materials Center maintains the GI seed
stock (slender wheat grass shown here) for those A/M accessions exhibiting
commercial potential.