浑善达克沙地的土地沙漠化过程研究  

Study on Land Desertification Process in Hunshandake Sandy Land

作　　者：刘树林[1] 王涛[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所/中国科学院沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《中国沙漠》2007年第5期719-724,共6页Journal of Desert Research

基　　金：中国科学院寒区旱区环境与工程研究所知识创新工程项目(O65044A001);国家重点基础研究发展规划项目(G2000048705)

摘　　要：借助TM/ETM+影像和GIS平台,采用实地考察与野外实验和室内分析整理相结合的办法,对浑善达克沙地土地沙漠化过程进行了初步研究。结果表明,过去50a来,浑善达克沙地经历了强烈的沙漠化发展。位于沙地中部正蓝旗的沙漠化土地从1987年的5 593.8km2发展到2000年的6 015.3km2,发展速率为32.4km2.a-1。2000年紧急启动的风沙源治理工程,一定程度改善了当地沙漠化发展态势,2005年正蓝旗共有沙漠化土地5 950.4km2,有约330.7km2的严重沙漠化土地得到了控制和逆转。其他大部分沙漠化土地虽有不同程度改善,但5a的时间里尚未发生质的变化。沙漠化过程是原生植被逐步被沙生植被和沙生先锋植被取代的过程;同时也是土壤粗化、贫瘠化和空间重新分布过程。随着土地沙漠化程度的加剧,起沙风速降低,输沙强度增大,沙地近地表表现出相对高风能环境。沙漠化过程以固定沙丘活化为主,主要有发育"马蹄形"风蚀洼地、"鱼钩"型沙丘和"串珠状"风蚀槽三种沙丘活化形式,最终导致景观支离破碎、不少地区出现了流沙连片的现象。同时,农田开垦引起土壤风蚀的危险,也不容忽视。This paper conducted preliminary study on land desertification process of Hunshandake Sandy Land, using TM/ETM＋ images from 1987 to 2005 and GIS software, and combining with field investiga- tion, observation experiments and laboratory analysis. The results show that aeolian desertification was strongly developing in Hunshandake Sandy Land during the past 50 years. The desertified lands of Zhenglan Qi located in the middle of the Sandy Land expanded from 5 593.8 km^2 in 1987 to 6 015.3 km^2 in 2000, with the development rate of 32. 4 km^2· a^-1. The ＂Sandstorm Source Control Project In and Around Beijing and Tianjin＂ was implemented since 2000, which restrained the developing tendency of desertification to some extent. There were 5 950.4 km^2 of desertifed lands in Zhenglan Qi in 2005, and about 330.7 km^2 of desertifed lands were controlled and reversed. Although the other aeolian desertified lands also were improved at different degrees, in only 5 years can not get essential change. Aeolian desertification processes of Hunshandake Sandy Land are both the process that original vegetation was replaced by psammophytes and pio- neer desert plants and the process that soil coarsening toward barren and spatial redistribution. Along with the desertification degree increasing, the threshold wind velocity declined and sand transporting intensity increased, and relative high wind energy condition occurred in surface boundary layer of sandy land. The main aeolian desertification process in Hunshandake Sandy Land is reactivation of fixed-dunes. Fixed and semi-fixed dunes were reactivated widely through three developing types： horseshoe wind-eroded depression, fishhook-shaped sand dunes and catenated wind-eroded slot, which ultimately resulted in very fragmented landscapes and shifting dunes conjoining each other in many areas. Also, wind erosion resulted from soil cultivation can not be ignored.

关 键 词：浑善达克沙地 沙漠化过程 沙丘活化 风沙地貌 

分 类 号：X144[环境科学与工程—环境科学]