Effect of application of coal powder and lime on alfalfa growth on copper polluted acidic soil.

摘要

The hypothesis that a combined treatment of copper-contaminated acid soil with lime and a coal powder decreases copper toxicity due to a synergetic effect of pH increase and association of Cu2+ ions in organomineral complexes was tested. A two-year-long pot experiment with alfalfa (Medicago sativa) was carried out on a pseudopodzolic soil (Dystric Planosol) contaminated with four Cu levels in the range 0-900 mg kg-1 soil. The amendments applied were lime, coal powder and a precomposted mixture of lime and coal powder. The compost and lime application increased yield and decreased copper content in plants at all levels of copper pollution. Coal powder alone depressed plant growth. The combined application of lime and coal powder maintained soil pHin the optimum range (5.1-5.6) during the whole experiment and had a pronounced effect on yield of the second and next crops, depending on the level of liming.