采用田间腐解试验 ,在研究不同腐解期玉米秸秆对土壤胡敏酸性质影响的基础上 ,利用酒精分级沉淀法对土壤胡敏酸进行分级 ,研究了不同腐解期土壤胡敏酸级分组成及性质变化。结果表明 ,在整个腐解过程中土壤胡敏酸由 A型转化为 P型又转化为 A型 ,呈现由复杂到简单又到复杂的变化趋势。不同腐解期土壤胡敏酸的级分组成不同。玉米秸秆更新土壤胡敏酸过程是一个双向过程 ,一方面使胡敏酸中结构复杂成分 (级分 1、2、3 )向简单化发展 ,另一方面一些小分子胡敏酸 (级分 6、7)随时间推移按 Rp→P→ A途径逐渐缩合。 Based on the study on the effects of corn stalks on soil humic acid in different decomposing stages, the soil humic acid was graded by alcohol fractional precipitation method. The effects of humic acid fraction Changes in composition and nature. The results showed that soil humic acid changed from type A to type P and type A during the entire decomposing process, showing a trend of changing from complex to simple to complex. Different decayed soil humic acid fraction composition. The process of corn stalks renewing soil humic acid is a two-way process that simplifies the development of complex components of the humic acid (fractions 1, 2 and 3) on the one hand, and on the other hand some small molecule humic acids (fraction 6 , 7) gradually condense by the Rp → P → A pathway over time.