Plant and Soil Reactions to Nickel Ore Processed Tailings1
- P. J. Sheets,
- V. V. Volk and
- E. H. Gardner2
Greenhouse and laboratory experiments were conducted to determine the effect that tailings, produced during the processing of nickeliferous laterite ores by a proposed U.S. Bureau of Mines Process, would have on plant growth and soil properties. The tailings contained soluble salts (7.6 mmhos/cm), NH4-N (877 µg/g), Ni (0.28%), Mn (82 µg/g DTPA-extractable), Cr (0.44%), P (2 and 6 µg/g acid F- and NaHCO3-extractable, respectively), and Ca and Mg (1.0 and 20.7 meq/100 g NH4Ac-extractable, respectively). Water leaching decreased the NH4-N concentration to 53 µg/g and the EC to 0.4 mmhos/cm by removal of (NH4)2SO4 and MgSO4 salts. Tall fescue (Festuca arundinacea Schreb.) was grown on Eightlar clay soil (skeletal, serpentinitic, mesic Typic Xerochrept) amended with 0, 223, 446, and 669 g tailings/kg soil and pure, unleached tailings for 32 weeks in the greenhouse. Seedling establishment of plants grown on soil amended at the highest tailings rate and the pure tailings was initially slow, but plants grown on soil amended at lower rates established readily and grew well. Plant P was <0.24%, while plant Ca concentrations were <0.45% throughout the growth period even though Ca(H2PO2)2 and gypsum had been added. Ammonium acetate-extractable Ca at the end of the growth period was <5.0 meq/100 g on all amended soils. The Mn, Ni, and Cr concentrations of plants grown on treated soils were within normal ranges, although soil-analysis values were higher than commonly found. It is recommended that the tailings be washed to reduce NH4-N and soluble salts prior to revegetation, and that native soil be added to the surface to reduce crusting.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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