几种侵蚀红壤中有机质和团聚体的关系

Relationship Between Organic Matter and Aggregates in Several Eroded Ultisols

以3种侵蚀红壤（轻度、中度、严重）为供试材料,利用干湿筛法获得其不同粒径的水稳性团聚体（〉4 mm,2～4 mm,1～2 mm,0.5～1 mm,0.25～0.5 mm）,分析团聚体中有机质的分布。结果显示,随着侵蚀程度的增强,〉0.25mm水稳性团聚体的含量逐渐下降,而团聚体的分散度却依次升高;无论何种侵蚀程度,湿筛后团聚体的组成均以小粒径团聚体（〈0.25 mm）占优势。轻度和中度侵蚀的红壤,其有机质含量随着团聚体粒径的增大而增大,严重侵蚀的则相反;侵蚀红壤有机质含量和〉0.25 mm水稳定性团聚体呈显著正相关,3种侵蚀红壤团聚体对土壤有机质的贡献为轻度侵蚀〉中度侵蚀〉严重侵蚀。

The solk water stable aggregates of different diameter （〉 4 mm, 2 - 4 mm, 1- 2 mm, 0.5 - 1 mm, 0.25- 0.5mm） were gained and determined by drying-wetting sieving method in three kinds of eroded （ slightly, medium, severely） ultisols. The paper studied the distributions of organic matter in aggregates. The result indicated that the content of 〉0.25 mm water-stable aggregate （WSA） took on a falling trend with the enhancing of erosion degree, but the dispersing percent of aggregate （PAD） went up. Small aggregate played an important role after moistened. As to slightly and medium eroded ultisols, the content of their organic matter increased with the enlarging of diameter of aggregate, but it was opposite to severely eroded ultisol. In eroded ultisols, soil organic matter had a marked positive correlation with the content of 〉0.25mm water-stable aggregates. The contribution of aggregate to soil organic matter is in the sequence of slightly 〉 medium 〉 severely in three kinds of eroded ultisols.