黄土区次降雨条件下林地径流和侵蚀产沙形成机制——以人工油松林和次生山杨林为例  

Generation mechanism of woodland runoff and sediment on Loess Plateau under hypo-rainfall—A case study of artificial P.tabulaeformis and secondary natural P.dadidiana stands.

作　　者：潘成忠[1] 上官周平[1] 

机构地区：[1]中国科学院水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室

出　　处：《应用生态学报》2005年第9期1597-1602,共6页Chinese Journal of Applied Ecology

基　　金：国家重点基础研究发展规划项目(2002CB111502);国家自然科学基金资助项目(30230290;90102012).

摘　　要：以黄土区两种常见森林植被(次生山杨林和人工油松林)长期定位观测试验为基础,从水量平衡和径流产沙机理出发,分析了次降雨条件下两种林地和荒地坡面产流产沙过程.结果表明,次降雨量在5.0～50.0 mm范围内,油松林和山杨林的林冠和枯枝落叶层总截留率分别为15.45%～56.80%和20.56%～47.81%,且随降雨量的增大而减小.与荒坡地相比,林地土壤入渗性能显著增强,尤其是0～20cm土层.分析表明,在一般降水条件下林地无径流产生;而在降雨雨强为2.5 mm·min-1和历时30 min条件下,山杨林地无地表径流产生,荒坡地的径流流速和径流挟沙浓度均为油松林地的23.5倍,而其径流剪切力和径流能量均为后者的8倍;油松林地的径流量和产沙量比荒地分别减少了87.6%和99.4%,与径流小区多年(1988～2000)观测平均值(分别为87.0%和99.9%)相近.Based on the long-term observation and from the viewpoints of water balance and runoff-and sediment generation, this paper studied the generation processes of runoff and sediment on two typical woodlands, artificial P. tabulaeformis and secondary natural P. dadidiana, and uncultivated slope-land in Loess Plateau under hyporainfall. The results showed that within the range of 5.0--50.0 mm rainfall, the total interception of canopy and litter was 15.45 % -- 56.80 % for P. tabulaeformis and 20.56 % -- 47.81% for P. dadidiana, and decreased with increasing rainfall. Woodlands had a higher soil water infiltration capacity than uncultivated slope-land, especially in 0--20 cm soil layer. Both the two woodlands did not generate runoff under regular rainfall. Under the assumed rainfall of 2.5 mm· min^-1 intensity and 30 min duration, P. dadidiana stand did not produce runoff, but the runoff velocity and sediment-carrying capacity of uncultivated slope-land were 23.5 times, and runoff shearing stress and energy were 8 times as much as P. tabulaeformis stand. The runoff-and sediment generation on P. tabulaeformis stand decreased by 87.6 % and 99.4 %, respectively, compared with those on uncultivated slopeland, which was well accorded with the average observed value in runoff plots during 1988--2000. The theoretical analysis on the generation mechanism of woodland runoff and sediment may be effective to evaluate the benefits of forest in soil and water conservation.

关 键 词：水土保持 产流产沙 森林植被 黄土高原 

分 类 号：S715[农业科学—林学]