Temporal and spatial variability of soil erosion in Dongbeigou Watershed in northern mountainous area, Hebei Province, based on Land Use/Cover Change(LUCC)
LV Meng-Quan, WANG Ji-Jun, JIANG Jing-Long, ZHANG Fu, HAO Xiao-Dong
1.College of Resources and Environment,Northwest Agriculture & Forest University 712100, Yangling, Shaanxi;2.Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources, 712100, Yangling, Shaanxi;3.Institute of Soil and Water Conservation of Chengde City, Hebei Province, 067000, Chengde, Hebei:China
Abstract:Land-use has a direct effect on the change of soil erosion intensity through changing vegetation cover, soil property and runoff velocity. The Dongbeigou Watershed with an area of 19.34km2 was chosen as the study area. Based on climate, vegetation coverage, soil, land-use survey and Quickbird image data in 1990 and 2009, the change characteristics of land-use and soil erosion were revealed by means of the shift matrix of land-use and Revised Universal Soil Loss Equation (RUSLE) supported by GIS. The results showed: the forestland increased from 38.56% in 1990 to 55.83% in 2009 compared to the decrease of grassland, cropland and barren land. The main conversion happened between forestland and grassland. The annual average soil erosion modulus decreased from 5136.13t/(km2·a) in 1990 to 1823.30t/(km2·a) in 2009. The soil erosion intensity decreased significantly. The area where the slight soil erosion (200-2500t/(km2·a)) happened constituted 32.78%, and the area where the moderate soil erosion (2500-5000t/(km2·a)) happened constituted 28.49% in 1990, whereas, in 2009 the area where slight soil erosion happened constituted 33.25%, and where little slight erosion soil erosion (<200t/(km2·a)) happened constituted 28.49%. The average soil erosion modulus of different land use types declined greatly, but there were great differences among the soil erosion modulus of different land use types. The soil loss rate happening in forestland and residential land was low, but the soil loss rate happening in barren land was high. The barren land is the key area of soil and water conservation in future.