Abstract: This paper studied the distribution of native zinc forms in coastal saline paddy soils with different salt contents under drainage condition and after applying decomposed organic material. The results showed that waterlogging was beneficial to the transformation of soil native zinc forms to those less available to plant in some degrees, suggesting the reduction of soil available zinc. Different salt contents significantly affected the variations of Zn bound to amorphous iron oxide (AFeO-Zn), Zn bound to tight humus (TOM-Zn) and silicate mineral Zn (MIN-Zn). Planting rice without the application of organic material was conducive to the depletion of exchangeable Zn (EX-Zn) and MIN Zn and the enrichment of Zn bound to carbonate (CAB-Zn), Zn bound to manganese oxide (MnO-Zn) and AFeO-Zn in rhizospheric soil, and the stronger zinc transformations in contrast to non rhizospheric soil. This induced that in rhizospheric soil, available zinc was close to its critical value which was higher than that in non rhizospheric soil. Organic material improved the transformation of MIN-Zn in rice rhizospheric and non rhizospheric soils, especially in rhizospheric soil with low salt content. With the increase of organic material incorporated with the soils, the transformation of MIN-Zn, MnO-Zn and CAB-Zn to EX-Zn, TOM-Zn and AFeO-Zn was promoted in rice rhizospheric soils with different salt contents, particularly with low salt content.

Key words: Zinc forms distribution, Organic material, Rhizosphere, Saline soil