Effects of fly ash pH on the uptake of heavy metals by chicory

Chicory was cultivated in a pot experiment using two soils of different pH. Treatments were NPK, fly ash (pH 8) + NP and fly ash (pH 12) + NP, respect ively. Another series of pots received heavy metals in soluble form additio nally to the described treatments. It was observed that fly ash causes gene rally a decrease in Zn, Cd, Ni and Cu concentrations of chicory. The reduct ion occurs both for the metals naturally present in the soil and, to a grea ter extent, for those added as salts. This effect is more evident when fly ash at pH 12, rather than that at pH 8, was used. The increase of soil-pH t hrough the fly ash addition is the major factor decreasing heavy metal avai lability. It was observed that potassium originating from fly ash is not av ailable for crop uptake.