Change of pH, organic carbon (OC), electrical conductivity (EC), nickel (Ni) and chrome (Cr) in soil and concentration of Ni and Cr in radish and lettuce plants as influenced by three year application of municipal compost

Abstract

In order to investigate the effects of applying municipal solid waste (MSW) on the amount of pH, organic carbon (OC), electrical conductivity (EC), nickel (Ni) and chrome (Cr) in soil, as well as the concentration of Ni and Cr in lettuce and radish plants, a field experiment was conducted as split-plot arrangement based on randomized complete block design with three replications in 2008. The main plot was municipal solid waste added to the soil in three levels (0, 20 and 40 ton ha -1 ) and the sub-plots were applied in 3 years, which comprised 2006, 2006-2007 and 2006-2008. The results showed that application of MSW in three years had significant effect on the amount of pH, OC, EC, Ni and Cr in soil (available and total) and plant organs (root and shoot). Application of 40 tons MSW ha -1 in three continuous years decreased the amount of pH and increased the amount of OC and EC in soil. The maximum amount of lead (Pb) and cadmium (Cd) (total and available) was accumulated in 40 ton ha -1 treatment, but the application of MSW in one-year and two-year treatments produced significantly different results compared to the control treatment. Three-years application (cumulative effect) at all levels of MSW increased the concentrations of available and total Ni and Cr in soil significantly. The amount of Ni and Cr in roots and shoots of lettuce and radish were increased in 40 ton.ha -1 treatment