Assessment of soil erosion at large watershed scale using RUSLE and GIS: a case study in the Loess Plateau of China

Abstract

Soil erosion is a serious problem in the Loess Plateau of China, and assessment of soil erosion at large watershed scale is urgently need. This study used RUSLE and GIS to assess soil loss in the Yanhe watershed. All factors used in the RUSLE were calculated for the watershed using local data. RUSLE-factor maps were made. The mean values of the R-factor, K-factor, LSfactor, C-factor and P-factor were 970 209 MJ km À2 h À1 a À1 , 0Á0195 Mg h MJ À1 mm À1 , 10Á27, 0Á33359 and 0Á2135 respectively. The mean value of the annual average soil loss was found to be 14 458 Mg km À2 per year, and the soil loss rate in most areas was between 5000 and 20 000 Mg km À2 per year. There is more erosion in the centre and southeast than in the northwest of Yanhe watershed. Because of the limitations of the RUSLE and spatial heterogeneity, more work should be done on the RUSLE-factor accuracy, scale effects, etc. Furthermore, it is necessary to apply some physical models in the future, to identify the transport and deposition processes of sediment at a large scale.

The tradeoff and synergy between ecosystem services in the Grain-for-Green areas in Northern Shaanxi, China

“…Soil retention is calculated as soil loss supposedly ignoring vegetation cover and soil erosion control practices minus the current LULC patterns and soil erosion control practices. According to locally developed specific methods calculating factors of the USLE for the Loess Plateau (Zhang et al, 2004;Fu et al, 2005), the equation is expressed as:…”

“…Therefore, simply borrowing the model with locally calculated factors may lead to deviation from the actual situation. This model has been criticized for being ineffective for estimating deposition and sediment yield under various conditions, especially in predicting gully erosion (Fu et al, 2005;Beskow et al, 2009). Overestimation may occur on slopes steeper than 30% owing to the USLE algorithms which are highly sensitive to slope gradients (Liu et al, 1994).…”

Assessment of soil erosion using RUSLE and GIS: a case study of the Yangou watershed in the Loess Plateau, China

“…The relative impacts of management options can be easily compared by making changes in the C-factor which varies from near zero for well-protected land cover to 1 for barren areas (Lee and Lee 2006). The reasonable methods to compute C-factor for large scale are extrapolating fromthe plot scale if there are basic data for plots, or evaluating qualitatively if there are no basic data (Fu et al 2005). A land use map of the study area derived from the Landsat Thematic Mapper image taken in 2003 was used as the basis for determining the C-factor values.…”

“…Depending on how they represent spatial variability of erosion processes, models can be categorized into lumped and distributed ones (Aksoy and Kavvas 2005). Both of the models can provide useful information for decision-makers and planners to take appropriate landmanagement measures (Fu et al 2005). …”

“…The problems of soil erosion and environmental degradation resulting from long-term anthropogenic influences and the inherent vulnerability of the Chinese Loess Plateau have always been of deep concern to relevant government departments and academic institutions (Xu et al 2009). In recent years, much work has been done on soil erosion assessment at plot or catchment scale (Kang et al 2001;Fu et al 2004), and some at regional scale (Yang et al 2002;Fu et al 2005). However, the quantitative assessment of spatially distributed soil erosion has not been adequately addressed, and more work should be done on this topic.…”