黄土丘陵沟壑区集水区尺度土地利用格局变化的水土流失效应  

Effects of land-use pattern change on soil and water loss at the catchment scale in the hilly and gully area of the loess plateau of China

作　　者：赵文武[1] 傅伯杰[1] 陈利顶[1] 吕一河[1] 刘永琴 

机构地区：[1]中国科学院生态环境研究中心系统生态重点实验室 [2]延安水文水资源勘测局,延安716000

出　　处：《生态学报》2004年第7期1358-1364,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金重大研究计划资助项目 ( 90 10 2 0 18) ;国家基金委创新群体资助项目 ( 4 0 3 2 110 1) ;中国科学院知识创新工程重要方向资助项目 ( KZCX3 -SW-4 2 1)~~

摘　　要：以陕北杏河集水区 1 985和 1 995年两期土地利用数据为基础 ,结合水文、DEM数据 ,定性分析了土地利用格局变化条件下的水土流失效应 ,其中采用双累积曲线法来界定土地利用格局基本没有变化的时间段 ,用 C值在坡度、距河流距离上的分布来表征土地利用格局 ,用不同时期降雨量 /径流量、降雨侵蚀力 /输沙率相对增加的比例来表征水土流失效应。研究结果表明 :(1 ) 1 981～ 2 0 0 0年 ,土地利用格局变化剧烈的年份为 1 990～ 1 991年 ,可以用 1 985、1 995年两期数据分别代表 2 0世纪 80年代和90年代的土地利用 ;(2 )从 2 0世纪 80年代到 90年代 ,杏河集水区的 C值有明显的增加趋势 ,在较陡坡度和距河流距离较近处 ,C值增加的幅度相对较大 ;(3)土地利用格局变化明显改变了降雨量 -径流量、降雨侵蚀力 -输沙率的关系 ,出现了从 2 0世纪80年代到 90年代 ,虽然降雨量 /降雨侵蚀力在整体上呈现明显下降的趋势 ,但是水土流失量 ,却表现出同比增加的现象 ,而且这种增加在不同月份也有差异。用本文中的方法来表征土地利用格局和水土流失效应 ,其结果具有较好的比配性 ,可以用来定性分析土地利用格局与水土流失的关系。但是 ,由于水土流失效应的表征方法没有考虑降雨的空间变异特征 ,该方法尚不适于雨量站点比较密集?The hilly and gully area of the Loess Plateau of China suffers some of the highest soil erosion rates on the Earth, and one of the most important reasons is irrational land-use. The study on the effects of land-use pattern on soil and water loss is helpful not only to the comprehensive watershed management but also to further understanding of landscape pattern and ecological process. A case study was carried out in Xinghe catchment of the Loess Plateau, and DEM, land use maps, rainfall and hydrological data were used in the qualitative analysis of land use pattern on soil and water loss. The land use pattern change periods were identified by double mass curves of rainfall-runoff and rainfall erosivity-sediment. The characters of land use patterns were denoted by the spatial distribution of C value on slope grade and the distance to rivers, and the change of soil and water loss in different periods were analyzed by the increased ratio of rainfall & runoff, rainfall erosivity & sediment discharge. The results showed that: (1) During the periods of 1981-2000, there was a sharp change in 1990～1991, and the land use status in 1980s and 1990s could be reflected by the land use maps in 1985 and 1995 respectively. (2) From 1980s to 1990s, the C value in Xinghe watershed increased obviously, especially on steeper slope grades and at the close distances to the rivers. (3) The change of land use pattern altered the relationships of rainfall-runoff, rainfall erosivity-sediment discharge obviously; runoff and sediment discharge in flood season increased from 1980s to 1990s, though rainfall and rainfall erosivity decreased in the same periods. In order to reduce soil and water loss, not only land use types should be changed, but also more attentions should be paid to spatial distribution of land use types. It is necessary to increase the land use types with lower C value on steeper slope grades and at the close distances to the rivers. The results of denoting land use pattern and soil & water loss were suited with each ot

关 键 词：土地利用格局 水土流失 集水区 C值 双累积曲线 

分 类 号：S157[农业科学—土壤学]