Metal bioavailability and uptake by Potato plants (Solanum Tuberosum L.) grown in soils amended with MSW Compost

Abstract

Abstract---A field experiment was conducted to determine the effects of MSWC (municipal solid waste compost) as an organic material source on the growth and the accumulation of heavy metals in potato plant (Solanum tuberosum L.) and to assess heavy metal loading and its bioavailability and trace metal speciation on the greenhouse soil. MSWC was applied to plots at 0, 80 and 160 T/ha rates as an oven-dry basis, and potato plants were cultivated under field conditions. Plant vegetative dry weight, potato yield and Zn, Cu, Ni, Pb and Cd contents in the leaves and tubers of potato and soil metal speciation and total and bioavailable metals of experimental soil were determined.MSWC amendments increased total and DTPA extractable metals in the soil compared with the control. Increase in bioavailable metal concentrations by the treatments were more marked than those of total concentration of metals. Metals entered soil by MSWC were mostly in mobile fractions. The mobility factor of metals was increased by MSWC treatments, and mobility factor of Cd was the highest among the metals.The effects of MSWC amendments on the vegetative dry weight and tuber yield of potato were found statistically important. MSWC application at 80 T/ha rate were supplied better yield results than that of control. Although MSWC led to greater dry matter at low application rates, 160 T/ha application rate of MSWC depressed plant growth, leaf dry matter and potato yield. However, MSWC applications brought about a sharp increase for heavy metals in the plant material. In the MSWC treatments, at 160 T/ha treatment, concentrations of Zn, Pb and Cd in potato tubers were exceeded limit values for edible vegetables. The resulting data demonstrate that metals were accumulated in potato tubers and safety food metal limit values for edible vegetables were exceeded by MSWC applications.