AbstractThe effect of geographical factors on soil erosion is an important aspect of the monitoring environment changes. The spatial relationship between soil erosion and its geographical factors was carried out. The results showed that soil erosion exhibited high selectivity of geographical factors. 94.5% of soil erosion occurred in areas less than 500 m, 85.3% presented on the areas between 15°- 35°, 57.2% distributed on southern slope, and 76.8% of strong erosion were found in garden land. It provided a basis for governing soil erosion, which was an important significance to local economic development

Wang, Xiaoming

Wu, Xilin

Elsevier - Publisher Connector 

Spatial Influence of Geographical Factors on Soil Erosion in Fuyang County, China 

 Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
1878-0296 © 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Conference ESIAT2011 Organization Committee.
doi: 10.1016/j.proenv.2011.09.333 
Available online at www.sciencedirect.com
 
 
Spatial Influence of Geographical Factors on Soil Erosion in 
Fuyang County, China 
Xilin Wu*1,a, Xiaoming Wang2, 
1. Department of Geography, Minjiang University, Fuzhou 350108, China 
2. Research Institute of Subtropical Forestry, CAF, Fuyang, Zhejiang 311400, China 
aemail: jieying_wu@sina.cn 
 
Abstract 
The effect of geographical factors on soil erosion is an important aspect of the monitoring environment changes. The 
spatial relationship between soil erosion and its geographical factors was carried out. The results showed that soil 
erosion exhibited high selectivity of geographical factors. 94.5% of soil erosion occurred in areas less than 500 m, 
85.3% presented on the areas between 15°- 35°, 57.2% distributed on southern slope, and 76.8% of strong erosion 
were found in garden land. It provided a basis for governing soil erosion, which was an important significance to 
local economic development. 
 
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of [name organizer] 
 
Keywords: soil erosion, geographical factors, Remote sensing (RS), Geographical Information System (GIS) 
Introduction 
Soil erosion is one of the most serious eco-environmental problems in China [1], which poses great 
hazards to soil degradation, agricultural production, water quality, natural resources and ecological 
security [2,3]. Protection measures to lessen these problems can be effectively carried out if the intensity 
and spatial distribution of soil erosion are known. Various models have been developed to simulate the 
process of soil erosion and assess its risk since the 1930s [4]. These models range from empirical 
Universal Soil Loss Equation (USLE) [5] and Revised Universal Soil Loss Equation (RUSLE) [6] to 
physical process-based models such as Erosion Productivity Impact Calculator (EPIC)[7], Kinematic 
Erosion Simulation Model (KINEROS)[8] and so on. Variables used in models are not always easy to be 
acquired, such as historical data requirement of neural-network method [9]. So, mapping soil erosion on a 
large scale is often impractical using these traditional models solely. The applications of GIS in estimating 
soil erosion were reviewed by Wilson and Lorang [10], as well as the difficulties and limitations of 
previous research being discussed. It was concluded that GIS and RS provide tremendous potential for 
improving soil erosion evaluation. In general, parameters of underlying surface features can be derived 
through RS images. In this study, information was extracted from RS images and field investigation with 
© 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Conference ESIAT2011 
Organization Committee.
2011 3rd International Conference on Environmental 
Science and Information Application Technology (ESIAT 2011)
Open access under CC BY-NC-ND license.
Open access under CC BY-NC-ND license.
2129 Xilin Wu and Xiaoming Wang /  Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
the study area of Fuyang Country, Zhejiang Province. Environmental database of watershed was 
established in the support of GIS. Quantitative evaluation and monitoring for spatial background 
characteristics of soil erosion were conducted by spatial overlaying of soil erosion intensity maps and 
geographical factors distribution. 
1 Materials and Methods 
1.1 Study area 
Fuyang Country is located in north of Zhejiang Province between 29°44ƍ~30°11ƍ58"N, 
119°25ƍ~120°19ƍE covering a total area of 1831.2 km2. Fuchun River runs through its center stretching 
about 52.0 km. All the rivers in study area belong to Fuchun River system. Fuyang is characterized by 
one river between two mountains with many mountains in southeast, northwest and hilly regions in center. 
Plains distribute along rivers and valleys. Average elevation of Fuyang is 300m, with maximum of 1067m 
and minimum of 6 m. Soils can be divided into five main groups: Red soils, Yellow soils, Limestone soils, 
Alluvial soils and Paddy soils. Fuyang lies in south edge of the northern subtropics with annual mean 
temperature of 16.1ć. The accumulated temperature of 10 ć in study area is 5100ć with frostless 
period of 232days and annual mean sunshine duration of 1995 hours. There are two main reasons for soil 
erosion: natural factors (terrain, precipitation, soil and vegetation) and anthropogenic factors (vegetation 
destruction, improper reclamation and mining). Because of high population density and intensive 
management, the human disturbance for hilly and mountain regions is very frequently. Coupled with low 
quality of forest, soil erosion often occurs, as well as landslide, debris flow and other natural hazards in 
local regions. 
1.2 Data and Study Method 
1.2.1 Data  
Landsat ETM+ image for study area of 2006 was collected, as well as land use map in the same year. 
DEM and soil map dated back to 1989 with scale of 1:50000 were also collected. Maps above were 
scanned, digitized and constructed using ArcGIS software. 
1.2.2 Extracting factors 
(1) Maps of elevation, slope and aspect 
Maps of elevation, slope and aspect were derived from DEM on the basis of ArcGIS. 
(2) Vegetation coverage map 
Normalized Difference Vegetation Index (NDVI) was used to calculate vegetation coverage in the 
regions with high forest coverage of 68.5%. The formula is given as follows:  
fc=(INDVIˉINDVImin)/(INDVImaxˉINDVImin). 
Here, the INDVI is value of NDVI, INDVImin is minimum of NDVI and INDVImax is the maximum of NDVI. 
(3) Land use and soil type maps 
Maps of land use and soil type were directly generated from those maps with scale of 1:50000 after 
vectorization. 
(4) Hydrology and topography maps 
Watershed is divided into plain, hilly, mountain, platform and other ecological regions by spatial 
analysis according to hydrological and topographic conditions, coupled with elevation, slope and other 
geographic factors. Raster data were converted into grid format with 25m×25m resolution. In addition, all 
the data should be fitted to map projection of Krasovsky_1940_ Transverse_Mercator for spatial analysis.  
1.2.3 Soil erosion intensity maps 
According to the national classification standards of soil erosion types, soils in Fuyang are eroded 
mainly by hydraulic power, which is characterized by erosion on slopes. Besides, gravity erosion can be 
2130   Xilin Wu and Xiaoming Wang /  Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
found in parts of mountain regions, such as landslide and collapse. Different degrees of soil erosion were 
classified by integration of the following materials: current land use maps, vegetation coverage maps, 
slope maps and indices from table1. Soil erosion intensity maps (Fig. 1) were generated through field 
survey. Given geographic factors, areas for soil erosion of different degrees were calculated. 
1.2.4 Correlation analysis between soil erosion and geographic factors 
The most important geographic factors that influence soil erosion are: elevation, slope, aspect, land 
use and soil type. In order to obtain the correlation between soil erosion and factors above, overlaying 
analysis was conducted, the tables of correlation between soil erosion and geographic factors were also 
computed. 
 
 
Fig. 1 Spatial distribution of soil erosion in the study area 
2 Results and discussions 
2.1 General characteristics of soil erosion 
Statistical results show that the soil erosion area of Fuyang is 1390.6 km2, accounting for 76.3% of 
total area. The primary soil erosion degrees are slight and moderate, accounting for 94.9% of total erosion 
area. Very strong and strenuous soil erosion is scarce, with proportion of only 3.8%. 
2.2 Relationship between soil erosion and slope, aspect 
Overlaying analysis of slope, aspect maps and soil erosion intensity charts was conducted. Statistical 
analysis (table 1 and table 2) shows that soil erosion mainly occurs in 15°~35° slope belt, accounting for 
2131 Xilin Wu and Xiaoming Wang /  Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
85.3% of total erosion area. The slope in 25°~35° regions cover the largest erosion area, accounting for 
58.0% of total erosion area. Vegetation covers consist mainly of tea trees, fruit trees and seedlings in that 
area, where the slope is steep with thin soil. Moreover, immoderate exploring and other unreasonable 
human activities are conducted over slope land, resulting in soil erosion in hilly regions, even more severe 
in some parts. It is easily understood that soil erosion is closely related to slope, the steeper the slope, the 
more severe erosion happens. Soil erosion in slope lands above 35° only accounts for 4.5% of total 
erosion area. The main reasons are that these lands have been conserved with high forest coverage and 
few human activities. 
As to aspect, soil erosion mainly occurs on sunny slope, accounting for 57.2% of erosion areaˈ
following with semi-sunny and semi-shady slope. Analysis shows that soil erosion has close relationship 
with aspect. With good water and heat conditions, south slope is suitable for agriculture cultivation. 
Agriculture activities focus on sunny slope, leading to corresponding soil erosion. 
Table 1 Related feature tables between soil erosion and slope in the study area 
Degree Level 
˘6° 6°~15° 15°~25° 25°~35° ˚35° 
area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% 
Very Slight Erosion 379.6  88.2  36.5 8.5  11.7 2.7  2.4 0.6  0.2 0.1  
Slight Erosion 15.9  4.0  62.3 15.8  317.1 80.2  0 0  0 0  
Middle Erosion 0 0 62.7 6.8  5.2 0.6  795.5 86.0  61.7 6.7  
Strong Erosion 0 0 0 0 57.2 99.0  0.1 0.2  0.5 0.9  
Very Strong Erosion 0 0 0 0 0 0 11.5 100.0  0 0 
Strenuous Erosion 0 0 0 0 0 0 0 0 0.9 100 
ratio/% 1.2 9.0 27.3 58.0 4.5 
Table 2 Related feature tables between soil erosion and aspect in the study area 
Degree Level 
Shade Semi-sunny Sunny Flat Semi-shade 
area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% 
Very Slight Erosion 38.6  9.0  106.5 24.7  183.3 42.6  4 0.9  98.2 22.8  
Slight Erosion 4.0  1.0  91.4 23.1  213.8 54.1  0 0 86.1 21.8  
Middle Erosion 4.4  0.5  179.2 19.4  548.4 59.3  0 0 193 20.9  
Strong Erosion 1.5  2.7  14.9 25.8  27 46.7  0 0 14.4 24.8  
Very Strong Erosion 0.4  3.1  2.9 25.4  6.1 52.7  0 0 2.2 18.9  
Strenuous Erosion 0 1.3  0.2 19.8  0.6 69.6  0 0 0.1 9.3  
ratio/% 0.7 20.8 57.2 0 21.3 
2.3 Relationship between soil erosion and elevation 
Overlaying analysis of soil erosion intensity maps and elevation map reveals that the lower the 
elevation is, the more severe the soil erosion is. Soil erosion mostly happens in regions below 500 m, 
accounting for 94.6% of total erosion area. The soil erosion areas of strong and very strong severe degree 
below 200 m are 29 km2 and 2.3 km2 more than those in 200~500 m zone respectively. Besides, the 
region above 500m accounts for a small proportion. Due to high elevation, inconvenient traffic, high 
forest coverage and agriculture producing cost, little human disturbance exists in regions above 500m, 
therefore, soil erosion less occurred. 
 
2132   Xilin Wu and Xiaoming Wang /  Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
Table 3 Related feature tables between soil erosion and elevation in the study area 
Degree Level 
˘200 m 200~500 m 500~800 m ˚800 m 
area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% 
Very Slight Erosion 427.5  99.3  2.8 0.7  0.2 0.0  0 0 
Slight Erosion 305.1  77.2  79.2 20.0  10.9 2.8  0.1 0  
Middle Erosion 262.8  28.4  599.8 64.8  61.7 6.7  0.7 0.1  
Strong Erosion 42.6  73.6  13.6 23.5  1.7 2.9  0 0 
Very Strong Erosion 6.7  58.6  4.5 38.8  0.3 2.6  0 0 
Strenuous Erosion 0.4  41.5  0.5 54.0  0 4.5  0 0 
ratio/% 44.4 50.2 5.4 0.1 
2.4 Relationship between soil erosion and land use 
Soil erosion is closely related to land use type. It is mainly concentrated on forest land and shrub 
grassland with middle or slight degree, and erosion area in these two types account for 88.3% of total 
erosion area. Although the forest coverage in study area is as high as 68.4%, the overall quality is still low, 
as well as the low stand volume with mean value of 29.9 m3/hm2, which is below the average level of 
40.5 m3/hm2 in Zhejiang Province. The coniferous, such as Pinus massoniana and Cunninghamia 
lanceolata, are main forest species, accounting for 52.5% of total forest land. Shrub and bamboo forests 
also cover large area with proportion of 22.0% and 19.1% respectively. The water and soil conservation 
functions of these forest species are weak, while the broadleaf forest with effective function only account 
for 9.7%. In addition, unreasonable exploring and cultivation also aggravate the soil erosion in parts of 
mountain areas. Results show that 76.8% of intensive and above occurs in garden plots, which suggests 
soil erosion in gardens is much serious in study area. For highly intensive management of economic crops, 
such as Phyllostachys edulis (Carr.) and drastic human disturbance, soil erosion often occurs in garden 
plots.  
Table 4 Related feature tables between soil erosion and land use in the study area 
Degree Level 
Farm land Garden land Forest land Shrub land Urban and water 
area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% area/km2 ratio/% 
Very Slight Erosion 158.1  36.7  38.9 9.0  9.7 2.3  3.8 0.9  220.1 51.1  
Slight Erosion 22.1  5.6  13.2 3.3  292.4 74.0  66.8 16.9  0.8 0.2  
Middle Erosion 23.1  2.5  36.1 3.9  714.8 77.3  150.4 16.3  0.7 0.1  
Strong Erosion 10.8  18.7  43.8 75.7  0.7 1.2  2.2 3.8  0.3 0.6  
Very Strong Erosion 1.5  13.3  9.4 81.7  0.1 0.8  0.4 3.5  0.1 0.6  
Strenuous Erosion 0.1  10.1  0.8 85.7  0 0.4  0 3.6  0 0.2  
ratio/% 4.1 7.4 72.5 15.8 0.1 
3 Conclusion 
Soil erosion shows significant spatial heterogeneity patterns. It mainly occurs in regions below 
500m, accounting for 94.5% of total erosion area. Slope has significant effects on soil erosion, which 
mainly occurs in 15°~35° slope area, accounting for 85.3% of total erosion area. Soil erosion shows high 
selectivity in aspect, it mainly occurs in south slope, covering 57.2% of total erosion area. Soil erosion is 
severe in garden plots, where 76.8% of strong and above degree soil erosion occurs. The integration of 
2133 Xilin Wu and Xiaoming Wang /  Procedia Environmental Sciences  10 ( 2011 )  2128 – 2133 
GIS/RS techniques with geographical factors is practicable and effective on monitoring soil erosion in 
large areas. The research can provide reference for local eco-environment protection and sustainable 
economic, social development. 
Acknowledgment 
Financial supports from 11th Five-Year national key scientific and technological project 
(2009BADB2B03) are highly appreciated. The authors wish to express their appreciation to Dr. Wang ku 
for his help with English language checking. 
 
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Spatial Influence of Geographical Factors on Soil Erosion in Fuyang County, China

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