for suiting the condition in Taiwan, Domestic scholars Huang in 1979 
studied R factor for Taiwan area according to geographic characteristics 
for local condition. He established average R factor contour map for 
whole Taiwan island using nonlinear regression equation and the 
relationship between average rainfall and R factor. The reference figure 
shows as figure 2. 
K — soil erodibility factor—the soil loss rate per erosion index unit for a 
specified soil as measure on a unit plot, the reference value shows as 
Figure 3. 
  
  
  
  
  
  
  
  
  
  
Figure 2 The K value reference figure Figure 3 The R value reference figure 
L —slop length factor—the ratio of soil loss from the field slope length under 
the unit plot conditions as above. 
S — slope steepness factor—the ratio of soil less from the field slope gradient 
under unite-plot conditions. 
Slope length and steepness is recorded by soil map unit area on aerial 
photographs, and can be interpreted from soil maps for farm planning 
purposes to help control erosion. Steeper slopes have greater soil erosion 
potential because runoff is more rapid, and longer slopes have more water- 
gathering capacity to move larger volumes of sediment. Slopes can be made 
shorter and less steep with terraces. 
This study produced slope and aspect information from ten meter contour line 
and on Figure 5. through digitizing transfer into Vector file and using the GIS to 
generate the slop and aspect date. 
Table 1. The C & P reference value 
  
  
  
  
  
  
  
  
  
  
  
C Value P. Value 
Forest 0.01 0.01 
Betel nut 0.025 0.14 
Urban 0.01 ] 
Bare ^ Collapsed |l 1 
Water 0 0 
C—=cover and management factor—the ratio of soil loss from an area with 
specified cover and management to that from a unit plot in tilled 
continuous fallow. This study extracted land cover factor as shown from 
Table 1., which consider classified landcover type and other references. 
139 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996