华北落叶松林不同坡位土壤含水量对降雨的响应  

Response of soil moisture content to rainfall at different slope positions in Larix gmelinii var.principis-rupprechtii plantation

作　　者：王梦飞 刘泽彬[2] 于松平 徐丽宏 郭建斌[1] WANG Mengfei;LIU Zebin;YU Songping;XU Lihong;GUO Jianbin(College of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration,Ecology and Nature Conservation Institute,Chinese Academy of Forestry,Beijing 100091,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]中国林业科学研究院森林生态环境与自然保护研究所国家林业和草原局森林生态环境重点实验室,北京100091

出　　处：《森林与环境学报》2024年第4期357-366,共10页Journal of Forest and Environment

基　　金：“十四五”国家重点研发计划课题“土石山区华北落叶松林水源涵养及固碳功能提升技术”(2022YFF1300404);中央级公益性科研院所基本科研业务费专项资金项目“森林坡面产流的时空变化及影响机制”(CAFYBB2020QB004);国家自然科学基金项目“黄土高原地区生物物理因素驱动下树干储水的抗旱机制及模拟”(32271959)。

摘　　要：为明确森林坡面不同坡位土壤含水量对降雨的响应差异,选取六盘山半湿润区华北落叶松林典型坡面为研究对象,于2022年5—10月连续观测降雨等气象因子,以及不同坡位(坡上、坡中和坡下)0~60 cm根系层土壤含水量变化,分析生长季土壤含水量对不同降雨事件的响应及其坡位差异。结果表明:土壤含水量存在坡位差异,其平均值表现为坡上>坡中>坡下,且土壤含水量的波动在坡中最大;降雨对土壤含水量的补给有坡位差异,降雨补给阈值在坡中最小,为1.9 mm,在坡下最大,为2.3 mm;不同土层土壤含水量对降雨的响应有坡位差异,在小雨事件中,各坡位0~20 cm土层响应速度最快,但在中雨和大雨事件中,坡中和坡上40~60 cm土层土壤含水量对降雨的响应早于20~40 cm土层,表明在坡中和坡上土壤中可能存在优先流。研究结果对于理解坡面土壤水分运移及其再分配有重要意义。To clarify the differences soil moisture content in response to rainfall at diverse slopes of forested hillslope,a typical hillslope covered by Larix gmelinii var.principis-rupprechtii plantation in the semi-humid zone of Liupan Mountain was selected for this study.Meteorological factors such as rainfall and variations in soil moisture content in the rhizosphere at 0-60 cm and different slope positions(upper,middle,and lower slopes)were observed continuously from May to October of 2022,and the response of soil moisture content to varied rainfall events and their slope position differences within the growing season were analyzed.Our results showed differences in soil moisture content among slope positions,with the mean values showing a upper>middle>lower slope pattern,with the fluctuations in soil moisture content being the greatest in the middle slope.Moreover,rainfall recharge of soil moisture content varied by slope,with the recharge thresholds being lowest(1.9 mm)in the middle slope and highest(2.3 mm)in the lower slope.Slope differences were also observed in the response of soil moisture content to rainfall at various rhizosphere levels.The response duration of soil moisture content in the 0-20 cm soil layer was the shortest for all slopes under light rainfall conditions.However,the duration of soil moisture content response was shorter in the 40-60 cm soil layer than in the 20-40 cm soil layer at the top and middle of the slope under moderate and heavy rainfall events.These observations indicated that there might be a preferential flow of water in the soil at the middle and upper slopes.The results of this study are important for understanding soil moisture movement and its redistribution on slopes.

关 键 词：华北落叶松林 土壤含水量 坡位差异 降雨响应 

分 类 号：S715[农业科学—林学]