Remediation of cadmium contaminated vertisol mediated by Prosopis charcoal and coir pith

Abstract

Metal contamination of soil due to industrial and agricultural activities is increasingly becoming a global problem, thereby affecting animal and human life, thus rendering soil unsuitable for agricultural purposes. Remediation of cadmium (Cd) contaminated soil (Vertisol) using agricultural by products as source of organic amendments, Coir pith - a by-product of the coir industry and Prosopis charcoal - prepared by burning Prosopis plant wood (Prosopis juliflora L.) was investigated. The alleviation potential of Prosopis charcoal and Coir pith on the negative effects of Cd in soil was evaluated in pot culture experiments with Vigna radiata as the test plant, a Cd accumulator. Cadmium addition to soil resulted in accumulation of Cd in all plant parts of V. radiata predominantly in roots. The influence of Cd in the presence and absence of organic amendments on the various biological and chemical parameters of the soil, on the levels of Cd accumulation and on the growth attributes of V. radiata has been assessed. Among the organic amendments, Prosopis charcoal was found to be more effective in reducing the bioavailable levels of Cd in the soil artificially spiked with Cd in graded concentrations of 0, 5, 10, 20, 40, 60, 80 and 100 micro g g-1 and its accumulation in V. radiata, thus resulting in an increase in the root, leaf and stem biomass. Coir pith, however, was effective in increasing the total mycorrhizal colonization of roots and second in reducing Cd levels in plants. Therefore, Prosopis charcoal was considered best for stabilization of Cd in soil.