Zinc (Zn) speciation was determined in a Zn pre-treated Andosol, Incep
tisol, and a Vertisol before and after adding phosphate. The fractions
obtained, i.e., soluble, exchangeable, iron-manganese (Fe-Mn) bound,
chelated and insoluble organic forms had a different distribution in t
he three soils. The exchangeable form predominated in the Andosol, fol
lowed by Fe-Mn oxide bound Zn and minor amounts of the chelated forms,
whereas Fe-Mn oxide bound Zn was very abundant in the Inceptisol and
Vertisol. Sizable amounts of the exchangeable form were also present.
Phosphate pre-treatment of the Inceptisol and Vertisol did not alter t
he distribution of the different forms of Zn, whereas in the Andosol t
he exchangeable as well as the Fe-Mn oxide bound Zn increased markedly
, chelated Zn also increased somewhat.