水旱轮作条件下紫色水稻土水稳性团聚体的研究表明：同无肥区和化肥区比较，施用９年有机肥后，土壤＜０．０１ｍｍ土粒（物理性粘粒）发生团聚的程度明显增强；有机微团聚体和Ｆｅ、Ａｌ－有机微团聚体的含量呈不同程度的增加；土壤微团聚体垒结疏松，孔隙稳定性增强，有机肥施用促进了土壤有机质和无定形氧化铁的变化是土壤水稳性团聚体改善的根本原因。 The study on water-stable aggregates of purple paddy soil under runoff-drought conditions showed that the degree of aggregation of <0.01mm soil particles (physical clay) after 9 years of application of organic fertilizer was higher than that of no-fertilizer zone and fertilizer zone Significantly increased; the content of organic microaggregates and Fe, Al-organic microaggregates increased to some extent; the soil microaggregates had a loose knot structure and increased pore stability; and the application of organic manure promoted soil organic matter and amorphous iron oxide The change is the fundamental reason for the improvement of soil water-stable aggregates.