Abstract: In order to approach the mechanism of zinc deficiency in the calcareous purple soil widely distributed in hilly regions of central Sichuan Province, eight forms of zinc were determined from 30 samples by sequential chemical extraction method and the data were treated by optimum regression and correlation analyses. There were remarkable differences among all forms of zinc, which were influenced by soil pH, texture, organic matter and carbonates. The carbonates not only enhanced the adsorption of zinc by soil oxides and clay minerals, but also adsorbed and immobilized it (2.70% of total Zn) by themselves. Soil pHand organic matter were the major factors affecting available zinc.

Key words: Calcareous purple soil, Zinc form, Influence factors