太湖流域典型土地利用类型土壤水分对降雨的响应  

Response of Soil Moisture to Rainfall in Typical Land Use Types in Taihu Basin

作　　者：李谦[1,2] 郑锦森[1] 朱青[1] 廖凯华[1] 杨桂山[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,南京210008 [2]中国科学院大学,北京100039

出　　处：《水土保持学报》2014年第1期6-11,共6页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41271109;41030745);中国科学院南京地理与湖泊研究所"一三五"重点项目(NIGLAS2012135005);领域前沿项目(NIGLAS2011YJ01)

摘　　要：基于太湖流域平原区典型土地利用类型(林地、菜地)不同深度(10,20,40,60cm)土壤水分以及降雨的监测数据,分析2种土地利用类型下土壤水分变化对降雨的响应模式。结果表明:(1)菜地表层土壤水分波动较深层剧烈,而林地不同深度的土壤水分变化模式相似;(2)菜地表层土壤水分对降雨的响应受初始含水量影响显著。初始土壤较干燥时,降雨入渗较快,10cm和20cm土壤水分对降雨的响应时间基本一致,而若初始土壤较湿润,土壤水分对降雨响应的早晚与土壤深度正相关;(3)菜地土壤在40cm深度出现明显分层,降雨入渗到该界面时停止下渗并不断累积而趋于饱和;(4)受冠层截留以及地表枯枝落叶对雨水吸持的作用,中小降雨事件难以引起林地土壤水分的显著变化,当发生较大强度的持续降雨时,林地深层土壤水分容易受到周边侧向壤中流汇水以及土壤大孔隙的优势流影响,而在集中性强降雨过程中,林地深层土壤水分变化则主要受土壤大孔隙的优势流影响。Precipitation and soil moisture at different depths（10, 20, 40, 60 cm） in forest and vegetable plot in Taihu basin were analyzed for characteristics of soil moisture variation and its response pattern to rainfall events. The result showed that： （1）The fluctuation of surface soil moisture was severer than that in deeper layers in vegetable plot, while soil moisture at different depths in forest had similar variation pattern. （2）In vegetable plot, the response of soil moisture in surface（0--20 cm） to rainfall was influenced by initial soil condition. Instantaneous response of soil moisture at 10 cm and 20 cm depths to rainfall was observed due to fast infiltration when initial soil was relatively dry, while normal downward response order occurred when initial soil was relatively wet. （3） An obvious less permeable soil horizon was observed at 40 cm depth in vegetable plot, where perched water table was observed due to surface infiltration and subsurface lateral flow. （4）In forest, medium and small rainfall events had tiny influences on soil moisture due to interception and water-holding by ground litter. Rainfall event with larger amount and longer duration contributed to the occurrence of water confluence by subsurface lateral flow and preferential flow through surface crack or soil pipe, which in turn recharged the soil layers in a ＂bottom-up＂ order, while in more concentrated large rainfall, surface crack or soil pipe connected by soil macropores was the main contributor to the occurrence of preferential flow, which quickly recharged deep soil layers.

关 键 词：太湖流域 土地利用 土壤水分 优势流 

分 类 号：S152.7[农业科学—土壤学] S157.2[农业科学—农业基础科学]