The quantity of black soil is degraded, and the main thing that remote sensing technology can investigate and detect at present is the area change. The main reasons for the area change of black soil and chernozem in this area are gully development related to soil erosion, desertification and the occupation of permanent buildings by human activities. Due to the influence of topography, groundwater and other factors, soil erosion in Songliao Plain mainly occurs in black soil area, and desertification and salinization mainly occur in chernozem area. According to the interpretation results of remote sensing data in different periods, the black soil degradation in this area can be divided into three levels: mild black soil degradation, moderate black soil degradation and severe black soil degradation. The salinization of chernozem can also be divided into three grades: mild salinization, moderate salinization and severe salinization.

The results show that the black soil near Suihua City and Harbin City is seriously degraded, which belongs to severe black soil degradation (Figure 3.5.2). Nenjiang, wudalianchi city, Keshan, Baiquan, Mingshui, Cyclobalanopsis, Yushu and Changchun belong to moderate black soil degradation. Hailun City, Suiling County, Qing 'an County and other areas belong to mild black soil degradation. It can be seen that the area adjacent to the saline-alkali land is seriously degraded by saline-alkali erosion. The black land in this area is not only affected by its own factors such as soil erosion, but also seriously eroded by salinization, and its influence can not be ignored.