关键词: 喀斯特, 石漠化土壤, 土壤养分, 酶活性, 土壤质量

Abstract:  In order to reveal the qualitative status of soils in rocky desertification region,different degrees of rocky desertification soils were collected from a typical karst region in Guizhou Province as research ob ject.The nutrients content and enzymatic activity were analyzed,based on field sampling and laboratory determination,and the changes of soil quality with different degrees of rocky desertification were explored,to provide the foundation for possible soil improvement and ecological restoration in rocky desertification areas.The results showed that soil pH significantly increased by 4.49%—5.80% in rocky desertification soils.Organic matter and total nitrogen content in rocky desertification soils were higher than those in no rocky desertification soil.Soil organic matter content was 1.02—2.99 times more，and total nitrogen con tent was 3.65%—24.82% more in rocky desertification soils.However,total phosphorus content and to tal potassium content significantly decreased in moderate and severe rocky desertification soils.Activities of soil ivertase，urease，dehydrogenase，cellulose showed obvious decrease as the rocky desertification ag gravated.From light to severe rocky desertification，soil ivertase activity declined by 22.33% —71.46%,soil urease activity decreased by 31.25%—80.14%.Soil dehydrogenase activity was 70.83% and 83.33% down,and soil cellulose activity declined by 55.0% and 80.0% respectively in moderate and severe rocky desertification soils． Alkaline phosphatase activity was only 24.78% of the no rocky desertifi cation soil in severe desertification soil.Therefore,the nutrients content and enzyme activities could be ap plied as critical indicators for evaluating the soil quality in various degrees of rocky desertification soils．

Key words:  Karst, Ｒocky desertification soils, Soil nutrient, Enzyme activity, Soil quality