关键词: 黑土, 侵蚀沟, 克拜地区, Corona影像, 动态变化

Abstract: Gully erosion can be widely observed on cultivated slopes in Black Soil Region of Northeast China. Today, vast areas have been permanently ruined by erosion gullies. In many places, the farmland has been deeply incised, leading to loss of arable land as well as fertile black soil. The erosion gullies in Black Soil Region also affect farming activities and threaten the villages. Global Position System (GPS) and photogrammetry are often used to study the process of erosion gully development in a small scale. However, the research of gully distributing pattern and its variation on a larger spatial-temporal scale is rarely reported, owing to lack of high-resolution satellite imagery in the earlier time. Nowadays, the declassified images from spy satellites are an important addition to the record of the Earth's land surface back to the middle stage of the 20th entury. In this paper, taking eastern Kebai area as an example, based on field investigation of erosion gullies, the CORONA images of 1965 acquired by spy satellites of USA and SPOT-5 images of 2005 were used to extract erosion gully and land use information. The interpretation signs of erosion gully were presented and the image character for different type of gullies was described in this paper. With the support of GIS software, the image interpretation was conducted to obtain two stages of gully distribution maps, then the line coverage of erosion gullies were interpolated to gully density map using Arc/info9.0. Based on those work, the spatial distribution of erosion gully development from 1965 to 2005 and its regional variation were analyzed. This study revealed that from 1965 to 2005, the extent of high gully density area enlarged and tends to be onnected with each other in eastern Kebai area. But the spatial distribution of erosion gully development is not uniform in the study area. There is a great difference on the gully density change along the ridge of Tongken River, which is related to the natural process of landform evolvement. The study also showed that the gully density increased sharply when forest land changed into arable land or grassland. The unreasonable land reclamation and land use change in Black Soil Region of Northeast China during the past decades may be an important factor in the process of gully formation and development. This study can provide data for research of land degradation process, soil and water conservation and agricultural sustainable development in Black Soil Region of Northeast China.

Key words: Black Soil, Erosion gully, Kebai Area, Corona imagery, Dynamic change