Dynamics Analysis on Development of Desertification in Hobq Desert

The study area is located in the east of Hobq Desert-Dalate County,in farming and pasturing interlocked area.Base on the 3S techniques and combined with the ground review,the Land-sat TM images of year 1987,1995,2000 and 2003 were interpreted.This study analyzed the changes of sandland by using the database of desertification dynamics from 1987 to 2003.RS and GIS software,such as Erdas8.6,Arcview3.3 and ArcInfo7.1 were used as interpretation tools.The dynamic mechanism of desertification development was discussed from the aspect of land changing direction.The results showed that: the area of desertified land during the four periods was in the course of decrease-increase-increase,however,the desertification degree showed the trend of decrease-decrease-increase.Seeing from the aspect of land changing direction,the largest dynamic change of desertification degree appeared in the period of 2000-2003.The transformation of each land use type to desertified land was the important cause of desertification,moreover,the transformation among land use types were mainly caused by the unreasonable manner of anthropogenic land use.