INTEGRATED ASSESSMENT AND ANALYSIS OF PHYSICAL LANDSCAPE PROCESSES THAT IMPACT THE QUALITY AND MANAGEMENT OF AGRICULTURAL WATERSHEDS
Location: Watershed Physical Processes Research Unit
Title: Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan Mountains Region, Southern Ningxia, China
Submitted to: Frontiers of Environmental Science and Engineering in China
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 15, 2010
Publication Date: August 17, 2011
Citation: Quan, B., Romkens, M.J., Li, R., Wang, F., Chen, J. 2011. Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan Mountains Region, Southern Ningxia, China. Frontiers of Environmental Science and Engineering in China. 5(4):564-572. DOI 10.1007/s11783-011-0348-9.
Interpretive Summary: Land management in China is of utmost importance because of its limited acreage in relation to the size of its population. Certain regions in China, especially the Loess Plateau, have seriously degraded over five millennia due to overpopulation and over exploitation. The Liupanshen region is probably the most severely region affected by soil erosion in China, with a diminishing and impoverished population. The Chinese Government has made major past and current effort and investment to improve the land management practices in this region. This paper describes the changes in land use over a 15-year period from 1986-2000. This work is part of a Ph.D. dissertation of the senior author, submitted to the faculty of Yang Ling University in Shaanxi Province. ARS scientists working in the soil conservation area using Landsat Imagery might find this work of interest relative to the technique and methodology used in this land use study.
This work was conducted in cooperation with the Joint Sino-US Center for Soil and Water Conservation and Environmental Protection between the Chinese Academy of Sciences and Ministry of Water Resources, Yangling, and ARS.
The Liupan Mountains are located in the southern Ningxia Hui Autonomous Region of China, which forms an important dividing line between landforms and bio-geographic regions. The populated part of the Liupan Mountains region has suffered tremendous ecological damages over time due to population pressure, excessive demand and inappropriate use of agricultural land resources. To present the relationship between land use/cover change and spatio-temporal variation of soil erosion, datasets of land use between the late 1980s and 2000 were obtained from Landsat TM imagery, and then spatial models were used to characterize landscape and soil erosion conditions. Also, soil erosion response to land use and land cover change were quantified and analyzed using data from geographical information systems and remote sensing. Soil erosion by water was the dominant mode of soil loss, while soil erosion by wind was only present on a relatively small area. The degree of soil erosion was classified into severity classes; slight, light, moderate, severe, and very severe. Soil erosion in the Liupan Mountains region increased between the late 1980's and 2000, both in terms of acreage and severity. Moderate, severe, and very severe eroded areas accounted for 60.65% of the total area. The lightly eroded area decreased, while the moderately eroded area increased by 368817 ha (22%) followed by severe erosion with 146552 ha (8.74%), and very severe erosion by 970678 ha (5.79%). Soil loss on sloping cropland increased with slope gradients. About 90% of the cropland was located on slopes less than 15o. Most of the increase in soil erosion on cropland was due to conversion of steep slopes to cropland and degradation of grassland and increased activities. Soil erosion was severe on grassland with a moderate or low grass cover and on dryland. Human activities, the cultivation on steep slopes and overgrazing of pastures were the main reasons for the increase in erosion severity.