喀斯特槽谷区侵蚀坡面的土壤质量评价及障碍因子

Soil Quality Evaluation and Obstacle Factors of Erosion Slop in Karst Trough Valley Area

[目的]为准确评价喀斯特槽谷区顺/逆层坡侵蚀坡面的土壤质量特征,筛选出适用于该地区的土壤质量评价方法,探析限制其土壤质量的障碍因子。[方法]以重庆市青木关喀斯特槽谷区顺/逆层坡面的5种典型土地利用类型(林地、草地、裸地、玉米地、辣椒地)为研究对象,利用主成分分析法结合Norm值建立评价指标最小数据集(minimum data set,MDS),并通过非线性土壤质量评价方法和隶属度函数对喀斯特槽谷区顺/逆层坡面的土壤质量进行评价。[结果](1)喀斯特槽谷区土壤质量评价指标最小数据集(MDS)包括毛管持水量、毛管孔隙度和全磷;(2)通过非线性土壤质量评价方法得出,逆层坡土壤质量(0.519)优于顺层坡(0.451),其中逆层坡林地土壤质量最优(0.653),辣椒地土壤质量最差(0.426);(3)非线性评价方法在顺/逆层坡的决定系数(R 2)均高于隶属度函数,因此喀斯特槽谷区更适合采用非线性评分模型;(4)顺/逆层坡侵蚀坡面的土壤质量障碍因子差异显著,仅有全氮为共同的障碍因子。[结论]适当增加草地和乔木林的覆盖能提高喀斯特槽谷区土壤质量,研究结果可因地制宜地为喀斯特槽谷区顺/逆层坡侵蚀坡面的土壤质量调控和生态恢复提供依据。

[Objective]In order to accurately evaluate the soil quality characteristics of the dip/anti-dip erosion slope in the karst trough valley screen out suitable soil quality evaluation methods and explore the obstacle factors limiting soil quality in this area.[Methods]Five typical land use types(forest land,grassland,bare land,corn land,pepper land)were selected as the research objects in Qingmuguan Karst trough Valley of Chongqing,and the minimum data set(MDS)was established by principal component analysis combined with Norm value.The nonlinear soil quality evaluation method and membership function were used to evaluate the soil quality of the diplanti-dip erosion Slope and down-slope in the karst trough valley.[Results](1)MDS of soil quality evaluation indexes in karst troughs valleys included capillary water capacity,capillary porosity and total phosphorus.(2)According to the nonlinear soil quality evaluation method,the soil quality of anti-dip erosion slope(0.519)was better than that of dip erosion slope(0.451).The soil quality of anti-dip erosion slope forest land was the best(0.653),and that of pepper field was the worst(0.426).(3)The coefficient of determination(R 2)of the nonlinear evaluation method was higher than the membership function in the dip erosion slope and the anti-dip erosion slope,so the non-linear scoring model was more suitable for the karst trough valley.(4)There were significant differences in soil quality barrier factors,and only total nitrogen was the common barrier factor.[Conclusion]Appropriately increasing grassland and forest cover can improve soil quality in karst trough and valley area.The results of this study can provide basis for soil quality control and rational fertilization of slope erosion along/against slope in karst trough valley according to local conditions.