RESPONSE OF SOIL EROSION TO ENVIRONMENTAL CHANGES AND HUMAN ACTIVITIES DURING QUATERNARY, LOESS PLATEAU, CHINA

In evaluating modern soil erosion and foretelling soil erosion characteristic of the future under the background of global changes, we are facing a great number of questions that can only be answered through a better knowledge of the past. This paper analyzed structures and characteristics of soil erosion systems on the Loess Plateau during Quaternary. Based on stratigraphyical, archaeological evidence, written historical records and previous works, the history of soil erosion in Quaternary was reconstructed. The soil erosion in the transitional period between dry-cool periods and wet-warm periods was more intensive than that in the dry-cool period or the wet-warm period. A chronological analysis of soil erosion on the loess plateau during Quaternary is presented. The intensive soil erosion occurred at 2.4M.a.B.P., 1.48M.a.B.P., 0.56M.a.B.P., 0.25M.a.B.P., 0.14M.a.B.P.and 0.01M.a.B.P.; and during the Holocene, the periods of intensive soil erosion were 7500a.B.P.-7000a.B.P.; 200BC-0AD; 1000AD-1600AD; and the 30's, 50's and the later 60's of this century. Under the background of paleoenvironmental reconstruction, it shows that the influence of geo-ecological environmental changes on soil erosion was obvious, especially during the transitional periods. The soil erosion, however, was not serious during geological periods due to the self-control mechanism of the system. The serious accelerated soil erosion has occurred in recent 2500 years because of the man-made devastation of vegetation and other human disturbance to geo-ecological environment.