Submitted to: Final CRADA Report
Publication Type: Other
Publication Acceptance Date: September 1, 2001
Publication Date: September 15, 2001
Under a Cooperative Research and Development Agreement the ARS, University of Maryland, Environmental Consultancy of Sheffield University and Viridian Resources LLC developed an effective method to phytoextract Ni and Co from contaminated or mineralized soils. The initial studies supported a utility patent for Ni and Co phytomining using hyperaccumulator plants, rare species which accumulate over 1% Ni. Several plant species were examined, and the Alyssum genus Ni hyperaccumulator plant species tall enough to grow as a biomass crop were selected for conversion to a new crop. These species evolved in southern Europe on serpentine soils. Diverse germplasm of several species was collected. The germplasm was evaluated for yield, growth form and other characteristics by growing all entries in a randomized complete block experiment on a Brockman gravelly loam in Josephine Co., OR. Analysis of shoots and yields were used to select parents for recurrent selection breeding of improved cultivars. Key agronomic variables were evaluated to effect on Ni accumulation in shoot biomass. These species are adapted to highly infertile (deficiency P, Ca, N and K) serpentine soils; low fertilizer rates gave full yield potential. Plants require vernalization to flower, and planting and plant spacing requirements were established experimentally. The plants were also shown to be an effective method to decontaminate soils contaminated by Ni-smelter emissions or mine wastes rich in Ni. Some remarkable abilities of the Alyssum species to phytoextract Ni were identified, including the increasing uptake of Ni with increasing pH, opposite the effect of pH on crop plant uptake of Ni. Harvesting the biomass using hay handling methods worked well. Ni could be easily recovered from biomass ash.