渭北旱塬植被恢复对土壤有机质和水稳性团聚体含量的影响

Effects of Vegetation Regeneration on Soil Organic Matter Content and Water Stable Aggregates in the Weibei Dryland

植被恢复可改变土壤水稳性团聚体的形成及其对土壤有机质的保护。通过对渭北旱塬礼泉县北部不同土地利用类型下土壤水稳性壤团聚体和有机质含量的分析,探讨了两者之间的关系。结果表明:>0.25 mm土壤水稳性团聚体百分含量,平均质量直径和土壤有机质(SOM)含量在林地和永久性荒地中较农地大,而农地土壤水稳性团聚体的分形维数较大。矩法参数(Cs)在农地和一年荒地中为负值,而在林地和永久性荒地为正值。土壤有机质与水稳性团聚体平均质量直径线性正相关,粒级小于0.25 mm的水稳性团聚体中有机质含量最小,随粒级的增加,有机质线性增加,表明存在于水稳性团聚体内部的有机质矿化程度降低,同时也表明有机质为水稳性大团聚体的形成提供了良好的物质基础。渭北旱塬植被恢复可提高土壤有机质和水稳性团聚体含量。

The formation of soil water stable aggregates and their protective effects on soil organic matter content can be changed by regenerating vegetation. The content of water stable aggregates and soil organic matter under different land-use types in north Liquan County,the Weibei Dryland was analyzed. The results showed that the percentage content of soil water stable aggregates larger than 0. 25 mm,mean weight diameter and soil organic matter content were higher in woodland and permanent wasteland than those in farmland,and the fractal dimension of water stable aggregates in farmland was higher than that in woodland and permanent wasteland. Moment method parameter（ Cs） was negative in farmland and one-year waste land but positive in woodland and permanent wasteland.There was a linear positive correlation between soil organic matter content and mean weight diameter of water stable aggregates. Moreover,the organic matter content in soil water stable aggregate with a diameter less than 0. 25 mm was the lowest,and it was increased linearly with the increase of diameter of water stable aggregate. Which revealed that the mineralization of soil organic matter within soil water stable aggregate was reduced,and soil organic matter provided a good material base for the formation of larger soil aggregate. Soil organic matter content and water stable aggregates can be improved by regenerating vegetation in the Weibei Dryland.