两种土壤质量变化的定量评价方法比较

土地利用和管理在时空尺度上影响着土壤质量变化的方向和幅度，土壤质量评价方法的选择和应用对了解土壤的变化非常重要，不同方法的比较分析可以了解方法本身的差异和优缺点。选取卧龙自然保护区6种典型的土地利用类型，以空间代替时间序列的方式，研究森林次生演替，人工林种植及农业土地利用方式对土壤质量的影响。采用了综合土壤质量指数法(QI)与土壤退化指数法(DI)两种定量研究方法。结果皆揭示灌丛有着较高的土壤质量值。依次为灌丛→自然林，次生林→撂荒地→人工林→坡耕地，坡耕地土壤质量值较低。为更好的比较两种方法的差异，提出了QI的相对指数值(QI')，结果显示QI'和DI有着非常好的线性相关，退化指数法的方法简单，比较易用．而综合质量指数法有着较好的生态学意义。

COMPARISON OF TWO QUANTITATIVE METHODS IN ASSESSING SOIL QUALITY IN DIFFERENT LAND USES

Land use and management practices greatly impact the direction and degree of soil quality changes in time and space.The selection and application of different comprehensive assessment methods are important.The comparison of them can reveal the difference and advantage of different methods.A study was initiated in the Wolong nature reserve,Sichuan province,China to elucidate the soil quality changes of natural secondary succession,forest planting and agricultural practices after deforestation in the humid mountainous region.The soil qualities of six land use types(natural forestland,grassland,shrubs land,secondary forestland,cultivated land and reforested land)were compared using two quantitative methods:the integrated soil quality index(QI)and soil deterioration index(DI).Both of the results showed that the cultivated land,grassland and reforested land had the lower values,while the shrubs land and secondary forestland had higher values.To compare the two methods more directly,a deduced index QI' based on QI value was developed.The results showed that DI and QI' had a very high linear correlation coefficient.Both methods were efficient in evaluation the soil quality levels and DI was a more simple way in soil quality assessment,while QI could show more ecological meaning.