Optimization of land use structure and spatial pattern for the semi-arid loess hilly–gully region in China

Optimization of land use structure and spatial pattern for the semi-arid loess hilly–gully region in China
Qingzhu Gao a,b,c, Muyi Kang c,*, Hongmei Xu d, Yuan Jiang c, Jie Yang e
a. Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
b. Key Laboratory for Agro-Environment & Climate Change, Ministry of Agriculture, Beijing 100081, China
c State key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
d National Climate Center, Laboratory for Climate Studies of China Meteorological Administration, Beijing 100081, China
e Department of Ecology and Environmental Science, Inner Mongolia University, Huhhot 010021, China
The semi-arid loess hilly–gully region in China has an extremely vulnerable ecological environment. Inappropriate land use — crop farming, overgrazing, and plantation forestry - has worsened soil erosion, intensified water shortage, and hence impeded the ecological conservation and agricultural development of the entire region in the past. Optimizing land use and vegetation cover and spatial pattern is conducive to achieving both ecological and economic goals in terms of controlling soil erosion, using water resources rationally and raising agricultural productivity. Changchuan Watershed, a typical small catchment in the semi-arid loess hilly region, was selected as the case study area to analyze the impacts of land use and land cover structure and associated spatial pattern on soil erosion and water consumption in the Watershed, through field investigation andmodel simulation. Land use structurewas optimized bymulti-objective programming, using remote sensing (RS) and geographical information system (GIS) techniques, analytic hierarchical programming (AHP) and expert consultancy. The digitized optimumspatial pattern embodying rationally-proportioned land use structure was obtained through GIS-aided redistribution of land use types. The optimized land use structure reapportioned woodlands, shrublands, grasslands, and croplands at 3.7%, 38.6%, 49.4%, and 6.3% of the land area respectively, compared to the current land use structure of 2.4%, 38.6%, 24.0%, and 12.6%, respectively, in the ChangchuanWatershed. In the optimized land use spatial pattern, croplands are mainly located in the riverside plain and check-dammed valleys and grasslands are widely distributed in the lower reaches of the basin, while shrublands are appropriately established in the middle and upper reaches of the river. A comparative analysis shows that the optimized land use structure, with well-designed spatial pattern is able to reduce soil erosion, enhance the utilization of water resources and raise agricultural productivity.
Keywords: Land use structure and spatial pattern; Ecological security; Soil erosion; Water consumption; Geographical information system (GIS); Multi-objective programming
Published in CATENA. 2010, 81(3): 196-202