青海湖克土沙地沙棘林的防风固沙机制与效益  

Mechanism and benefit of wind-prevention and sand-fixation of Hippophae rhamnoides forestation in Ketu Sandy Land around Qinghai Lake

作　　者：吴汪洋[1] 张登山[1,2] 田丽慧[1] 魏殿生[1] 赵超[1] 贾飞飞[1] 

机构地区：[1]北京师范大学环境演变与自然灾害教育部重点实验室,北京100875 [2]青海省农林科学院,西宁810016

出　　处：《干旱区地理》2014年第4期777-785,共9页Arid Land Geography

基　　金：林业公益性行业科研专项"青海湖周抗寒抗旱固沙植物筛选与快繁研究"(201004025)

摘　　要：沙棘造林是青海湖克土沙地主要治沙措施,通过改变风速廓线垂向风速增加幅度、增加地表粗糙度和改变风沙流结构的机制实现沙棘林的防风固沙效益。根据2010-2012年连续3 a的沙棘沙丘与流动沙丘的春季风沙观测和植被调查,沙棘沙丘的风速廓线对数递增规律、输沙量和沙粒粒径的指数递减规律均被破坏;2012年沙棘沙丘在1 m高度以下的防风作用增加到22.75%,总体固沙效益较2010年增加近10%;同时,沙棘林的防风固沙效益随着风速增大而减弱,随植株高度与冠幅增加而增强。综合风沙防护机制与效益,沙棘造林技术在克土沙地以及整个高寒沙地生态治理中极具推广意义。Hippophae rhamnoides is a pioneer species of controlling desertification with strong ecological improve- ment and adaptability. Since 2008 when the measure of Hippophae rhamnoides forestation was firstly implemented in Ketu sandy land in the east of Qinghai Lake, the areal wind-sand activities and hazards have been obviously de- creased, but the functional mechanism and promoting feasibility of this measure in the high-altitude and cli- mate-cold areas need a far-researching and brief evaluation. Through a series of field wind-sand and vegetation ob- servations in each spring of 2010,2011 and 2012, the wind-profiles and wind-flow structures of both H. rhamnoides dune and mobile dune could be compared, and mainly analyzed the mechanism and benefits of wind-prevention and sand-fixation by rhamnoides under some statistics of wind speed amplification, surface roughness, sand transport, etc. Firstly, the logarithmic law of wind-profile of the rhamnoides dune was totally broken, and as well as the expo- nential law of sediment discharge and sand-grain size distributing with the height, those were reflected by a higher wind increasing rate in the low and middle layers, an increasing percentage of sand transport in the upper layer, anda major distribution of coarser grain in the middle layer, which all were basically caused by the vertical lifting func- tion of air flow and air energy accumulation in the plant canopies. Secondly, the benefit of H. rhamnoides wind-pre- vention changed with the height and the year. The wind-prevention function of the low layer is 2.0-3.7 times that of the middle layer, and 4.0-7.2 times that of the upper layer. Moreover, the average wind-prevention effects under the height of one meter increased to 22.75% in 2012 over twice as many as in 2010. Also, the benefit of H. rhamnoides sand-fixation increased yearly which is about 80% in 2010 and 88.9% in 2012 under a wind speed of 10 meters per minute. Thirdly, the two benefits would decrease slowly with the increasing of the wind velocity, but g

关 键 词：沙棘造林 防风固沙 风速增加幅度 风沙流结构 

分 类 号：S793.6[农业科学—林木遗传育种]