Dynamic changes of cropland based on fractal theory and its driving forces in arid oasis

Taking the typical Yutian oasis in arid southern Xinjiang Region as the study area, applying 3S techniques(RS, GIS and GPS) and fractal theory, several parameters such as the fractal dimension(D), stability index(SI) and fractal dimension change(ΔD) of cropland, were calculated in four separate years(1976, 1989, 1999 and 2001). The dynamic changes of cropland area were analyzed qualitatively according to the physical meaning of these parameters. Furthermore, by using statistical data of past years and principal component analysis, eleven driving forces resulting in temporal-spacial changes of cropland area were analyzed quantitatively. Results indicate that the primary factors which influence on dynamic changes of cropland area within 26 years are the socio-economic development level, population growth, scientific and technological progress in agriculture, and restrictions of water and soil resources. The research results are of great significance to the reasonable utilization and sustainable development of cropland in the oasis of arid areas.