太湖流域丘陵区两种土地利用类型土壤水分分布控制因素  

The controlling factors of soil moisture distribution under two typical land-use hillslopes in a hilly region of Taihu Lake basin

作　　者：徐飞[1,2] 赖晓明[1,2] 朱青[1] 廖凯华[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所,流域地理学重点实验室,南京210008 [2]中国科学院大学,北京100049

出　　处：《生态学报》2016年第3期592-599,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金(41271109,41301234);中国科学院南京地理与湖泊研究所“一三五”重点项目(NIGLAS2012135005)

摘　　要：为探究太湖流域丘陵区典型土地利用类型(如竹林地和茶园)土壤水分的控制因素,在不同深度土壤水分定期观测的基础上,根据前7d降雨量将研究时段划分为干旱状态和湿润状态,利用分类与回归树(CART)方法得出不同干湿状态下土壤水分分布的主控因子,并借助典范对应分析(CCA)定量分析不同土地利用类型、不同土壤深度土壤水分格局与环境因子关系。结果表明:(1)高程、土地利用类型和土层厚度对土壤水分分布的相对贡献率最大,但在不同干湿状态下其影响程度存在差异;(2)干旱状态时土壤水分主要受高程、坡度、地形湿度指数(TWI)和剖面曲率等地形因素的作用,而土层厚度和粘粒也分别为0—20 cm和20—40 cm深度土壤水分的主控因子;(3)在湿润状态下,茶园0—20 cm土壤水分的主控因素为地形因子,在20—40 cm则以土壤性质为主,竹林地两个深度的土壤水分受地形和土壤性质的作用都很强,其中20—40 cm深度土壤水分与环境因子的关系较0—20 cm深度更为复杂。Soil moisture is one of the most important factors in terrestrial ecosystems. Adequate knowledge of its spatio- temporal variability is critical to many scientific and practical applications. We explored the factors controlling moisture distribution in soils under typical land-use types （i.e., bamboo forest and tea garden） in a hilly region of Taihu Lake basin. In situ soil moisture measurements were made at different depths, and these were classified as dry or wet conditions, based on the precipitation during the previous 7 d. The main controlling factors were identified by using the classification and regression tree （CART） method. Canonical correspondence analysis （CCA） was then applied to quantitatively analyze the relationships between soil moisture and environmental factors under different land-uses at different soil depths. The results show that： （ 1 ） the relative influences of elevation, land use, and soil thickness on soil moisture distribution were larger than those of other environmental factors in most cases. Together these accounted for more than 50% of the total variation in soil moisture. However, their relative contributions differed between dry and wet conditions. （2） In dry conditions soil moisture was mainly affected by topographic indices such as elevation, slope, topographic wetness index （TWI） and profilecurvature. Soil thickness and clay content also significantly affected soil moisture at 0--20 and 20--40 cm depths, respectively. The main factors controlling soil moisture in dry conditions varied with soil depth, but not with land-use type. This finding was different from that of a previous study, in which the study area had similar landforms and climatic conditions. This may be due to the effects of spatial scale. （3） In wet conditions, topographic indices and soil properties were the main factors controlling soil moisture in tea gardens at 0--20 and 20--40 cm depths, respectively. Both topographic indices and soil properties were the main controlling factor

关 键 词：太湖流域 土壤水分 环境因子 主控因子 

分 类 号：S152.7[农业科学—土壤学]