Abstract
Organic acids and sugars are essential constituents of root exudates and have the potential to alter solubility and
bioavailability of trace metals. Present study was conducted to evaluate the effect of exogenous application of
glucose and acetic acid on the extractability of nickel (Ni), zinc (Zn) and lead (Pb) from contaminated soil. Soil
was contaminated by adding metals and then equilibrated at field capacity for 35 days. Thereafter soil was
amended with glucose and acetic acid and incubated at room temperature and field capacity for 30 days. Soil
samples were taken after 5, 10, 20 and 30 days and analyzed for AB-DTPA extractable metals. Results showed
that glucose and acetic acid initially enhanced the AB-DTPA extractable Ni and Zn compared to that with
unamended soil, but decreased with time. In case of Pb, glucose enhanced its extractability. On the other hand, at
5, 10, 20 and 30 days of incubation, extractability of Pb decreased with acetic acid application. It was concluded
that easily decomposable organic acids may temporarily enhance the metal availability to plants whereas that of
Pb could decrease through precipitation of Pb as sparingly soluble compounds like PbSO4 and PbCO3. However
further research is needed to know the mechanism of Pb retention in calcareous soils upon acetic acid
application.
