北方农牧交错带土地利用结构特征定量研究——以西辽河流域为例

Quantitative analysis of land use structure characteristics over the farming——pastoral zone in the West Liaohe river basin,northern China

北方农牧交错带是我国东、中部地区的重要生态屏障,西辽河流域处于北方农牧交错带的东段三北交界区,属于典型的生态脆弱区,近年来由于人类活动和自然环境的变化,该地区土地利用变化剧烈。为实现农牧交错带土地合理开发利用,而县级尺度是土地持续利用、管理和规划的最佳尺度,因此,文中以西辽河流域为研究区域,在运用RS与GIS技术获取研究区2015年土地利用数据的基础上,从土地利用总体组合类型、土地利用程度和土地利用结构区位意义等视角在分县尺度上定量评价了西辽河流域的土地利用结构特征。研究表明:(1)西辽河流域2015年土地利用组合类型齐全程度较低,且以耕地、林地和草地为主,说明西辽河流域土地利用的整体功能较差。(2)从空间分布来看,流域西南侧和东部的农区土地利用组合类型齐全程度较高,呈现耕地、林地和牧草地相间分布的特点;流域西北侧的半农半牧区未利用地所占比重较高,土地利用程度整体偏低。(3)对农牧交错带来说,各旗县耕地和林地区位意义相对较突出,草地区位意义不明显。据此,西辽河流域应在维持林地与耕地数量稳定的基础上,加强牧草地保护,防止土地沙漠化与水土流失。(4)研究结果表明对于农牧交错区,多样化指数、集中化指数与地类组合类型数之间的相关性并不高,应主要考虑农林牧用地的数量与空间布局是否合理。

As the intersection area and transitional zone of agriculture and animal husbandry,farming-pastoral zone of northern China is the important ecological barrier for east and central China.Affected by the increase of population as well as environmental degradation,great changes haven taken place in the structure and intensity of land use in the West Liaohe river basin which is located in the east of farming-pastoral zone of northern China.It is necessary to study the land use structure characteristics over the farming-pastoral zone.This research took the West Liaohe river basin as a case,by using the remote sensing land use date in 2015,the characteristics of land use structure at county level were quantitatively analyzed through quantitative geographical method.The results showed that： 1） The number of combination type was less and the overall function was poor; the first major land use combination was cropland-woodland-pasture in the West Liaohe river basin in 2015.2） Combination of land use types was relatively abundant in the agricultural area of southwest and east of watershed.Cropland,woodland and pasture were alternately distributed in the above different land use combination zones.The index of land use degree was in the low level and the proportion of unused land was high in the farming-pastoral area of northwest of watershed.3） The cropland and woodland had relatively outstanding location meaning in most counties,but the pasture did not have corresponding prominent location meaning although our study area was located in a farming-pastoral zone.According to the above result,we should not only maintain the stability of cropland and woodland,but strengthen the pasture protection to prevent land desertification and soil erosion.4） The correlations of diversification index,centralization index and combination type of land use were not high,so we should mainly considered whether the number and spatial distribution of cropland,woodland and pasture were reasonable in a farming-pastoral zone.