黄土高原土壤裸露与景观格局关系——以延安市宝塔区为例

土壤裸露是水土流失具体的空间表现,同时又是导致进一步水土流失的重要因素。由人类和自然相互作用下形成的景观格局对土壤裸露具有深刻的影响。为深入探讨二者间的内部联系,文章选定位于黄土高原的延安市宝塔区为研究区,分别就景观格局的类型组成和空间结构,分析其与土壤裸露的关系。研究结果可知人为活动强度较大的区域土壤裸露程度较高,在景观类型上,表现出滩地、农村居民点、其他建设用地、低覆盖度草地及山区旱地等景观类型的土壤裸露值较高,另外,从景观组成来看,农牧组成为主的流域土壤裸露值明显高于其他流域;通过景观空间结构与土壤裸露的关系分析,可知个体单元型态、空间构型以及整体多样性等景观空间结构特征,均对土壤裸露程度具有不同大小的指示意义,其中又以景观聚集度及平均斑块面积与土壤裸露程度有强烈负相关。

RELATIONSHIP BETWEEN SOIL BARENESS AND LANDSCAPE PATTERN IN THE LOESS PLATEAU:A CASE STUDIES ON THE TOWER REGION OF THE YAN′AN CITY

Soil bareness is sort soil erosion leading to a stronger soil erosion. There is complicated relationship between soil and landscape pattern resulted from human activities and geological processes. The Tower region of the Yan'an City in the Loess Plateau is used as typical area for the studies of soil bareness, types and structure of landscape. According to the differential landscape pattern in an individual watershed, it is classified into agriculture and pasture area; agriculture, pasture and forestry area; agriculture and forestry area; and forestry and pasture area. The degree of soil bareness is analysed based on each of landscape type and distinguished as urban and town landscape; dry farming landscape; lawn landscape and forestry lands cape.It is not numerically proportional between the degree of soil bareness in the watersheds and landscape types. The soil bareness is closely related to the landscape structure, spatial distribution and diversity characteristics. The analysis of drainage system in the area can illustrate the relationship between the degree of soil bareness and landscape patterns. The values of soil bareness in Xigou and Fengfuchuan are higher than those in other drainage areas, which require systematical drainage management and environmental protection. Human activities are closely related to the soil bareness in those areas such as built-up area, residential area, and hilly area.In the Tower region of Yan'an City, the proportional distribution of agricultural, pasture, and forestry areas could be used in a micro-scale to explain the degree of soil bareness. Generally more the landscape types have, worse the soil bareness.In conclusion, the relationship between soil bareness and landscape types is complicated in the Loess Plateau. Soil bareness is process of soil erosion and the seriousness of soil bareness might be represented by the amounts of landscape pattern, which is also related to human activity and environmental conditions.