摘要
不同地区冲积扇上农地发育特征的对比可以揭示环境条件与农地发育的关系。本文以Lansat卫星ETM+遥感影像、DEM和野外考察资料为基础,研究了祁连山、贺兰山与吕梁山三个地区山前冲积扇的地貌特征和扇上农地的发育特征,探讨了影响冲积扇上农地发育的因素。结果表明,吕梁山地区扇上农地比例最高,自扇顶到扇缘均有农地发育,其次为祁连山地区,农地主要发育在一些被黄土覆盖的冲积扇的老扇面上,贺兰山地区冲积扇上农地比例最低,农地多分布在扇缘区域;物质组成是影响冲积扇上农地发育的直接因素;相关性分析表明,祁连山和吕梁山地区冲积扇上的农地发育受黄土沉积过程影响显著,而贺兰山前冲积扇上农地发育更多地受冲积扇地貌过程的影响。
Comparison between agricultural land on alluvial fans of different regions could reveal the relation between agricultural land development and environment. This paper uses the Landsat RS images, data of DEM and field exploration to investigate characteristics of alluvial fans and agricultural land on alluvial fans at Qilian Mountain, Helan Mountain and Lueliang Mountain regions, and discusses factors influencing the development of agricultural land on alluvial fans.
Due to the great difference between drainage basins, alluvial fans at three regions also have different area scales; and they also have different loess covering degrees~ alluvial fans of Lt^liang Mountain have the highest area ratio of agricultural land that covers almost the whole fan surface, and Qilian Mountain has medium ratio that covers the older fan surface of some alluvial fans, and Helan Mountain has the lowest ratio that mostly covers fan toe areas. Slope distribution of agricultural land shows that most of agricultural land is developed at alluvial fan region lower than 2°, but Qilian Mountain and Lueliang Mountain regions, which both have higher loess covering degree, have agricultural land developed at alluvial fan region higher than 2°, and utilization proportion of agricultural land on fan region with the same slope increases along with the increase of fine materials on alluvial fan surface.
Distribution of agricultural land on alluvial fans shows that materials directly control the development of agricultural land. Correlative analysis between indexes of alluvial fans, drainage basins and agricultural land shows that loess depositing process, fan processs and fan shape influence the development of agricultural land at different degrees alternatively, and loess depositing process is the primary factor influencing agricultural land on alluvial fans at Ltiliang Mountain and Qilian Mountian, but fan process is the main factor at Helan Mountain. T＇he development of agricultural land on alluvial fans is more influenced by fan process that is mainly determined by drainage basin characteristics than by fan shape.
出处
《地理研究》
CSCD
北大核心
2006年第6期985-993,I0002,共10页
Geographical Research
基金
国家自然科学基金项目(40271013
40401005)资助
关键词
冲积扇
农地
祁连山
贺兰山
吕梁山
alluvial fan； agricultural lands Qilian Mountain；Helan Mountain
Lueiliang Mountain
作者简介
李新坡（1974-），男，河南新安人，博士研究生。研究方向：地貌学与环境演变。
