近40 a黑土典型区坡沟侵蚀动态变化

研究黑土区坡面侵蚀与沟谷侵蚀的动态变化对于正确认识黑土侵蚀的发生发展过程、制定合理的侵蚀防治对策具有重要理论与实际意义。该文以克拜东部黑土区为例，从1965年美国侦查卫星Corona影像和2005年法国Spot-5高分辨率遥感影像上提取侵蚀沟、植被、土地利用等信息，结合地形、降雨及土壤资料，以通用土壤流失方程为基本框架建立坡面侵蚀定量估算模型，在此基础上，对近40 a坡面侵蚀和沟谷侵蚀的动态变化进行深入分析。结果表明：研究区坡面侵蚀以轻度侵蚀为主，中度和强度侵蚀面积比例很小；40 a来坡面侵蚀总面积变化不大，但侵蚀强度的变化存在一定的地区差异；研究区1965年有侵蚀沟1 682条，2005年增加到2 561条，侵蚀沟平均每年侵吞耕地5.23 hm2；40 a来研究区坡沟侵蚀产沙比约为3.5︰1，总体上以坡面土壤流失为主。研究结果可为黑土区水土流失综合治理提供科学依据。

Dynamic change of hill slope and gully erosion in typical area of black soil region during the past 40 years

It has significant theoretical and practical value to conduct the research on dynamics of hill slope and gully erosion for better understanding soil erosion process and drawing up protection measures in the black soil area of Northeast China. In this paper, taking eastern Kebai black soil area as an example, high resolution satellite images, including the Corona spy satellite images of 1965 and Spot-5 images of 2005, were used to extract two periods of information such as gullies, vegetation, land use, etc. The spatial data of terrain, precipitation and soil, as well as the attracted data from the images were used to develop a hill slop erosion model based on the framework of universal soil loss equation (USLE). Thereafter, the hill slope and gully erosion dynamics during the past 40 years was analyzed. The results showed that hill slope erosion in this area was dominated by light erosion grade. The area of moderate and heavy erosion grades only occupied a small portion. Although the total area of hill slope erosion changed just a little, the change of hill slope erosion grade varied from place to place. The number of gullies in the study area increased from 1 682 in 1965 to 2 561 in 2005. Farmland area was swallowed by growing gullies at a speed of 5.23 hm2 each year. The ratio of hill slope erosion and gully erosion was approximately 3.5:1, suggesting that the sediment mainly came from the hill slope. The research result could provide a scientific basis for controlling water and soil loss in black soil area of Northeast China.