Abstract:The micro-structure of several typical redoxi-morphic features of Hydragric Anthrosols were analyzed by combining micro-morphological observation and Electronic Energy Disperse Spectrometer (EDS) determination of micro-zone chemical composition. Their formation mechanisms were suggested. The results showed that, root pore/fissure coating was formed through the enrichment of oxidized ferrous iron (Fe2+)on the surface of root pore or fissure, and the oxidation took place on the surface of Al-silicate clay mineral. The formation of rizospheric concentric iron-ring involved a self-organized process of reaction-transfer-reaction feedback, which leaded to the formation of banded iron-rich and iron-poor zones. Bleached coating can be separated as iron (and/or manganese)-depleted and clay-depleted ones, which were obviously different from each other in micro-structure and chemical composition. The later not only had more loss of iron and manganese but also was accompanied by destruction of Al-silicate clay.