祁连山东段土壤水分时空分布特征及其与环境因子的关系

Spatial and temporal variations of soil moisture and its relationship with environmental factors in the east section of the Qilian Mountains

基于时域反射仪（TDR）观测的土壤水分数据,探讨了祁连山东段旱泉沟流域2009年土壤水分的时空分布特征,并利用典范对应分析（CCA）方法分析了海拔、坡度、坡向、坡位、地貌类型、土地利用类型、土壤孔隙度等7个环境因子与土壤水分时空分布的相关关系。研究结果表明：在整个观测期间,灌草地和林灌地的土壤含水量最高,灌木地、林地次之,然后依次为退耕还草地、农地、退耕还林地和荒草地;海拔、坡向、土壤孔隙度和土地利用类型是影响土壤水分季节动态分布的主要因子,且不同月份土壤水分含量的主要影响因子各不相同,7月份与坡向相关性最大,8、9月份土壤水分含量与土地利用类型相关性最大,10月份与海拔相关性最大;研究区内23个样点0-10 cm土层含水量的总体变异系数（CV）最大,10-20 cm土层含水量的总体CV最小,且样点1和9以及样点14-17的土壤剖面含水量的CV较大;土壤孔隙度对土壤水分垂直分布的影响最为显著,坡位、坡向与海拔的影响次之,而地貌类型、坡度和土地利用类型的影响较小。

With the method of Canonical Correspondence Analysis（CCA）,this study discussed the spatial and temporal distribution characteristics of soil moisture in the Hanquangou watershed of the Qilian Mountains and analyzed its relationship with the environmental factors（e.g.,altitude,slope,aspect,slope position,landform types,land-use types and soil porosity）.The results indicated that：（1） The soil moisture of shrub-grassland and shrub-woodland was the highest during the study period,and then followed by shrub,woodland,grassland retrieved from cropland,cropland,woodland retrieved from cropland,and natural grassland;（2） Altitude,slope,soil porosity and land-use types are the main factors that affected seasonal dynamics of soil moisture,and the main impacting factors in each month were also different.For example,the factors were mainly associated with the aspect in July,with land-use types in August and September and with altitude in October;（3） The total coefficient of variation（CV） of soil water in 0～10 cm of 23 plots was the maximum,while the CV of 10～20 cm was the minimum;（4） The effects of soil porosity on the vertical distribution of soil moisture were the most significant,and then followed by slope position,aspect and altitude.This study provides a theoretical basis for the future establishment of mesoscale simulation of the spatial distribution of soil moisture in the Qilian Mountains.