Abstract: This paper studied the distribution of native ferric 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 increase of amorphous iron oxide (A-FeO), complexed Fe (Com-Fe), DTPA-extracted Fe and activity coefficient of iron oxide (ACIO) in saline soils tested whileas crystalline iron oxide (C-FeO) almost had no change, suggesting the transformation of soil other unknown ferric forms to C-FeO, and that Com-Fe and DTPA-extracted Fe in low saline soil increased more significantly than those in high saline soil. Planting rice without the application of organic material was beneficial to the enrichment of Com-Fe and DTPA-extracted Fe and the depletion of A-FeO and C-FeO in rhizospheric soil, and the lightly lower ACIO than that in non-rhizospheric soil. Organic material improved the transformation of native ferric forms to Com-Fe and A-FeO in rice rhizospheric and non-rhizospheric soils, particularly in rhizospheric soil with low salt content, and significantly increased DTPA-extracted Fe and ACIO in these soils.

Key words: Ferric forms distribution, Organic material, Rhizosphere, Saline soil, soil fertility., Phyllostachys praecox forest, mulching management, biomass