腾格里沙漠东南缘人工植被区降水入渗与再分配规律研究  

The infiltration and redistribution of precipitation in revegetated sand dunes in the Tengger Desert, Shapotou,China

作　　者：王新平[1] 李新荣[1] 康尔泗[1] 张景光[1] 周海燕[1] 杨诗秀[2] 雷志栋[2] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙坡头沙漠试验研究站,兰州730000 [2]清华大学水利系,北京100086

出　　处：《生态学报》2003年第6期1234-1241,共8页Acta Ecologica Sinica

基　　金：中国科学院知识创新工程资助项目 (KZCX1 -1 0 -0 3 -0 1 );中国科学院寒区旱区环境与工程研究所知识创新工程资助项目(CACX2 1 0 0 3 1 );国家重大基础研究资助项目(G2 0 0 0 0 4870 4)~~

摘　　要：试验于 2 0 0 1年 8月 1 7日至 9月 30日在中国科学院沙坡头沙漠试验研究站进行 ,主要利用时域反射仪 ( TDR)连续测量土壤剖面水分含量的方法 ,观测受植物根系吸水、蒸散作用影响下的人工植被荒漠灌木柠条 ( Caragana korshinskii)群落区固定沙丘降水入渗与再分配过程。土壤体积含水率由水平埋设在植物根系剖面内 1 2个深度层次 ( 5～ 2 0 0 cm)的时域反射仪探头每小时自动测定 1次。天然降水条件下的土壤入渗速率由入渗深度与相应的入渗时间之比值计算得到。结果表明 :在 7次不连续降水过程中 ,土壤入渗速率与降水强度呈简单线性相关关系 ,土壤入渗速率约为降水强度的 1 0倍强。然而当次降水过程中降水强度小于 0 .46mm/h时 ,土壤入渗速率约为 0 cm/h,此时的降水对人工植被固定沙丘区的土壤基本上没有水分补给作用。受荒漠灌木柠条根系吸水作用的影响 ,其根系密集剖面深度 40～ 1 40 cm内降水水分入渗积累不明显。降水入渗速率及入渗深度受土壤剖面初始含水率多寡而变化 ,干燥土壤剖面有助于提高入渗速率及入渗深度。降水以后随着时间的推移 ,区域环境内空气温度、湿度等气象条件适宜 ,柠条生长进入相对旺盛阶段 ,其根系密集层 1 40 cm深度处土壤含水率在总体上下降的过程中 ,表现出昼消夜长的趋势 。Forty years of revegetation using mainly Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou has established a dwarf\|shrub and herbaceous cover on sand dunes. Situated in southeast Tengger Desert at 1330 m elevation, it has an average annual rainfall of 191 mm with 83% received in May\|September. Precipitation, as the sole source of water replenishment in the semi\|arid area, plays a pertinent role in sustaining the desert ecosystem. The redistribution of infiltrated moisture through percolation, root extraction and evapotranspiration pathways was investigated. Experiments were conducted in the growing season for 45 days (17 August to 30 September 2001) on revegetated sand dunes. TDR probes were inserted horizontally at the depths of 5, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, and 200 cm layer below the ground surface in the dwarf\|shrub of Caragana korshinskii community to record volumetric soil moisture at hourly intervals. Other essential meteorological and soil parameters were evaluated. Seven rainfall events each of 1 5～40 7 mm intake occurred during the experimental period. Rainfalls were sporadic with widely different intensities. For the 40 7 mm rainfall episode with 3 4 mm/h maximum intensity and 5 4% antecedent volumetric soil moisture, maximum infiltration rate attained 0 42 mm/min. Infiltration rates varied greatly with individual rainfall quantity and antecedent soil moisture, with drier soil profile facilitating infiltration. Relationship between infiltration rate and rainfall intensity is linear, with infiltration rate at 10 times the magnitude of rainfall intensity. At rainfall intensity <0 46 mm/h, no soil moisture is gained. Root withdrawal of soil water and evapotranspiration (reaching 69%～90% of precipitation) restricted the wetting front penetration. A 40 mm rainfall at 1 50 mm/h intensity permitted wetting to 60 cm depth; a similar 40 7 mm rainfall at a lower 0 49 mm/h intensity limited wetting to <40 cm. The concentration of roots at

关 键 词：荒漠生态系统 土壤水分 入渗 水分平衡 人工植被 固定沙丘 柠条 

分 类 号：S152.72[农业科学—土壤学] S154.1[农业科学—农业基础科学]