1975-2008年塘背河小流域土壤侵蚀时空变化特征分析

An Analysis of Temporal and Spatial Variation Characteristics of Soil Erosion in Tangbei River Small Watershed from 1975 to 2008

塘背河小流域是国家首批开展小流域综合治理试点的41条小流域之一,为了科学、系统的探究其土壤侵蚀变化规律以及水土保持治理成效。基于Arcgis地理信息系统平台,采用中国土壤流失方程(CSLE)对1975-2008年塘背河小流域土壤侵蚀时空变化特征进行了分析。结果表明:塘背河小流域土壤侵蚀状况得到了明显改善,土壤侵蚀面积已由1975年的12.20 km^2减少为2008年的3.40 km^2,治理度达72.13%,1998-2008年间土壤侵蚀面积虽有增加,但主要集中在轻度和中度侵蚀等级;土壤侵蚀改良以塘背河小流中游的来溪村和下游的都田村最为显著,土壤侵蚀空间格局已由1975年的集中连片式转变为2008年的零星分散式;1975-2008年塘背河小流域土壤侵蚀等级整体向较低等级转移,期间,1998-2008年,土壤侵蚀等级出现了向侵蚀高等级转移的情况,但其转移面积较少且主要向轻、中度侵蚀等级转移,流域内土壤侵蚀整体改善状况良好。

Tangbei River small watershed is one of the first 41 small watersheds in the pilot of comprehensive management of small watershed, in order to scientifically and systematically study the soil erosion change law and the effectiveness of soil and water conservation. Based on the ArcGIS geographic information system platform, the temporal and spatial characteristics of soil erosion in Tangbei River small watershed from 1975 to 2008 are analyzed by using the Chinese soil erosion equation （CSLE）.The results show that： the soil erosion in Tangbei River small watershed was improved significantly, the soil erosion area decreased from 12.20 km2 in 1975 to 3.40 km2 in 2008, and the control degree was 72.13 %, although the soil erosion area increased in 1998-2008, but mainly concentrated in mild and moderate erosion grade. The soil erosion improvement was most remarkable in Laixi Village in the midstream and Dutian Village in the downstream.The spatial pattern of soil erosion changed from the concentrated distribution in 1975 to sporadic distribution in 2008. From 1975 to 2008, the overall level of soil erosion in Tanghei River small watershed was transferred to lower grade, and from 1998 to 2008, the soil erosion grade was transferred to high grade, but its transfer area was less and mainly transferred to light and medium erosion. The overall improvement of soil erosion in Tangbei River small watershed was good.