红壤性水稻土晶态氧化铁主要为针铁矿，并伴随少量的赤铁矿．红壤性水稻土中针铁矿的铝同晶替代量明显低于其母土（红壤），而针铁矿的晶胞参数ｂ和ｃ则是红壤性水稻土高于其母土．红壤性水稻土中赤铁矿的铝同晶替代量和晶胞参数ａ则与其母土相似．．据此认为红壤性水稻土中赤铁矿来源于母土；而针铁矿部分来源于母土，部分是由原有的赤铁矿和针铁矿的还原产物重新结晶形成的．随着水稻土的发育，赤铁矿逐渐下降，最后消失；针铁矿则相对增加，同时针铁矿中铝替代量也逐渐下降 The crystalline iron oxides in red paddy soil are mainly goethite with a small amount of hematite. The replacement amount of aluminum isotope of goethite in red paddy soil was significantly lower than that of native soil (red soil), whereas the unit cell parameters b and c of goethite were higher in red paddy soil than in native soil. The amount of aluminum isobaric substitution and the unit cell parameter a of hematite in red paddy soil are similar to that of its parent soil. . According to this, the hematite in the red paddy soil is derived from native soil, while the goethite is partly derived from the native soil and partly from the recrystallization of the original hematite and goethite reduction products. With the development of paddy soil, hematite gradually decreased and finally disappeared; while goethite increased relatively, while the replacement amount of aluminum in goethite decreased gradually