不同腐解期玉米秸秆对塿土胡敏酸基本性质及级分变异的影响

Effect of corn straw on the fraction variation and properties of humic acid in lousoil during different decaying periods

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。

On the basis of studying the properties of humic acid in the soil with application of corn straw in different decaying time, the alcohol precipitation technique was used for classifying soil humic acid into 7 fractions and the fraction composition of humic acids and their properties were researched. The results showed that the type of humic acid changed from type A to B and then to A during the whole decaying periods of corn straw. Humic acid changed from complex to simple and then to complex again. The fractional composition of humic acid differed as the decaying time going on. The process of renewal of humic acid by corn straw has two direction , One was that it made the complex fractions become simple ,and the other was that some small molecular humic acid condensed from type R p to P then to A as the time going on.