A Greenhouse Screening Trial to Evaluate the Response of Selected Vegetation Grown on Copper-Nickel Tailing

Abstract

A greenhouse screening trial was conducted to identify plant species useful in revegetation of !NCO copper-nickel tailing. Study objectives were to evaluate species growth and development in response to fertilization and to assess the accumulation of heavy metals in vegetation grown in tailing. With few exceptions, the physical and chemical charateristics of the tailing were found to lie within the range of properties of Minnesota soils. The tailing lacks organic matter; is deficient in nitrogen, phosphorus, and potassium; and may contain elevated levels of soluble salts and heavy metals. A fertilizer treatment was formulated to supply adequate to optimal quantities of essential plant nutrients. Three fertilizer treatments providing 50, 100, 150 percent of the optimal rate were tested in the trial. Nine woody tree and shrub species and 23 herbaceous grass and legume species demonstrated an ability to tolerate copper-nickel tailing as a growing medium. Plant response to tailing fertilization was favorable with peak biomass production generally achieved at the highest fertilization rate. However, caution is advised in applying excessive fertilizer to fresh tailing in that this practice may antagonize plant toxicities to soluble salts or heavy metals. Concentration of heavy metals were generally below suggested tolerance levels for plants and animal forage. Legumes tended to accumulate higher concentrations of copper and nickel, and metal uptake of most plants was positively correlated with the rate of fertilization.