东北典型黑土区坡沟侵蚀耦合关系

Coupling Mechanism of Slope-gully Erosion in Typical Black Soil Area of Northeast China

东北黑土区是中国重要的商品粮基地,但是严重的水土流失给其粮食产量带来了严峻考验。论文在遥感和GIS支持下,选择黑龙江省乌裕尔河和讷谟尔河两流域包含的东北典型黑土区作为研究区,以USLE模型和SPOT 5影像为基础,分别获取了2005年研究区的坡面侵蚀量和侵蚀沟分布数据,据此分析了典型黑土区坡面侵蚀和沟蚀之间在不同等级、坡度、坡向等方面的耦合关系。研究发现微度侵蚀和轻度侵蚀是坡面侵蚀主要区域,沟蚀发展程度比较剧烈;坡度小于5°时,坡度是沟蚀产生的制约因素,当大于5°时,坡度已经不是侵蚀沟形成过程中的主要控制因素;阳坡坡面侵蚀量高于阴坡的坡面侵蚀量,坡向在东北典型黑土区不是影响沟蚀发育的首要因子;侵蚀强度在2 500 t/(km2.a)以下的地区,随着坡面侵蚀量的增大侵蚀沟密度增大,而当大于2 500 t/(km2.a)以后,侵蚀沟密度比较稳定。

Black Soil Area of Northeast China is one of the most important marketable grain bases in China, but serious soil loss bring the crucial challenge to the marketable grain production. In this paper, supportad by Remote Sensing and Geographic Information System, taking typical Black Soil Area of Northeast China which is located in the Wuyuer River and Nemoer River basins as study area, based on USLE model and SPOT 5 imagery, the amount of soil erosion on hillslope and gully distribution data in 2005 were obtained respectively. Then the coupling relations be- tween hillslope erosion and gully erosion of different grades, slopes, aspects and so on were ana- lyzed. The results showed that slight erosion and light erosion were the main hillslope eroded area in the study area. Gully erosion was much serious and had a great potential for development. When the slope was below 5°, slope was the key factor causing gully erosion. However, when the slope was above 5°, slope was no more the important factor causing gully erosion. In addition, it showed that the amount of hillslope erosion on sunny slope was higher than shady slope, but for the gully erosion, aspect was not the key factor affecting the formation of gully erosion in Black Soil Area of Northeast China. In areas with an erosion intensity smaller than 2500 t/（ km2· a） , erosion gully density increased with the amount of hillslope erosion. However, When it is greater than 2500 t/（ km2· a）, the erosion gully density would be comparatively stable.