The changes of land use and the temporal & spatial characteristics of salt-affected lands on the regional scale

Yucheng city in Shandong Province was taken as the typical Fluvo-Aquic soil area in this paper. With the utilization of three different stages remote sensing images and groundwater depth spatial map, soil type spatial map, groundwater salinity spatial map of covering the study area, the support of multitemporal analysis method, the dynamic change of land use is studied in typical Fluvo-Aquic soil area, the temporal and spatial evolution of salt-affected lands is emphasized. The study results show that the areas of land use types of 3 different temporal stages are different in the study area, the area of salt-affected lands is 5 340 hm(2) in 1987, 3 670 hm(2) in 1994 and 2 000 hm(2) in 2002. From the spatial distribution, spatial location of most of salt-affected lands in 1994 follows the distribution of salt-affected lands in 1987, but the few of new saline soil spots come into being too. So the area of salt-affected lands decreased from 1987 to 2002. Comparing the distribution of salt-affected lands in 2002 with in 1994, the results are similar to the regime from 1987 to 1994, which explains the difficulties of improvement of salt-affected lands.