Effects of pH in polluted soils on the amount of heavy metals uptake by mulberry plant

Abstract

Polluted soils collected from mulberry fields in Annaka City, Gunma Prefecture, were adjusted for the pH values from 4.5 to 6.9 and the effects of soil pH on the mulberry plant growth and the plant availability of Cd, Zn and Pb were investigated. The plants grown in the soils were determined for the dry matter yields, which were found to be decreased according to the acidity of soil. In comparison with soil pH, heavy metals in the soils less influenced the plant growth. The Cd, Zn and Pb concentrations in the mulberry plant had scarce relationship to those in the soils, but the amounts of the elements taken up by the plants had close correlations with their concentrations in exchangeable+carbonate forms in the soils. Soil pH would control the concentration of heavy metals in the plants through the inhibition of mulberry plant growth. The plant availability of Cd, Zn and Pb is dependent on their concentrations in the exchangeable and carbonate forms in soils.