探究岩溶地区石漠化过程中土壤团聚体稳定性水平及养分特征,为推动该区域内土壤修复和植被恢复工作提供理论支持.以喀斯特高原山地潜在、轻度、中度和强度石漠化4种不同等级的土壤为研究对象,对0～20 cm 土层内4种土壤团聚体(大于2 mm,0.25～2 mm,0.053～0.25 mm,小于0.053 mm)的分布特征和3种养分(有机碳、全氮和全磷)的变化趋势进行分析.结果表明:①不同石漠化环境中团聚体含量随着粒径的增大而增高,粒径大于0.25 mm的团聚体含量比例均占约70％.②强度石漠化样地的团聚体稳定性指标MWD、GMD和SSSI均高于轻度,并与潜在和中度样地出现显著性差异.③样地环境石漠化程度依次为潜在、轻度、中度、强度,但团聚体中有机碳、全氮、全磷从大到小的变化趋势为强度、轻度、中度、潜在,粒径分布和石漠化等级对团聚体有机碳、全氮含量变化有显著的影响,小粒径团聚体的有机碳、全氮含量高于大粒径团聚体.对土壤养分的起主要贡献作用的粒径为大于0.25 mm.
Response of Soil Aggregate Stability to Soil Nutrients of Different Rocky Desertification Levels in Plateau Mountains
This paper understands stability and nutrient characteristics of soil aggregates in the process of rocky desertification in karst areas,which provides theoretical support for promoting soil restoration and vegetation res-toration in the region.With four kinds of soils with different degrees of rocky desertification which is potential,mild,moderate and severe rocky desertification in plateau mountains as the research object,an analysis was con-ducted the distribution characteristics of four soil aggregates(＞2 mm,0.25～2 mm,0.053～0.25 mm and＜0.053 mm)within 0～20 cm of the soil layer and the trend of changes in three nutrients(organic carbon,total nitrogen,and total phosphorus).The results were as follows:①The content of aggregates in different rocky desertification environments increases with the increase of particle size.The proportion of aggregate content with particle size＞0.25 mm is about 70％.②Average diameters(MWD and GMD)and soil structural stability index(SSSI)were higher than those of the mild rocky desertification sample,and showed significant differences from the potential and moderate rocky desertification sample.③The change trend for rocky desertification soil was potential＞mild＞moderate＞intensity whereas the change trend of organic carbon,total nitrogen,and total phosphorus for rocky desertification soil was intensity＞mild＞moderate＞potential.The particle size distribution and desertifica-tion level have a significant impact on the changes in organic carbon and total nitrogen content of aggregates.The organic carbon and total nitrogen content of small particle size aggregates is higher than that of large particle size aggregates.The particle size that contributes mainly to soil nutrients is＞0.25 mm.
soil aggregatestabilityaggregate nutrientsthe process of rocky desertification
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