Remote Sensing application in soil erosion studies on the loess plateau
According to the erosion types and characteristics in different geomorphologic locations, small watershed can be divided into three sections: rill-interrill erosion section, gully-gravity erosion section and deposit section of channel system. The land use and erosion types corresponding to the different sections can refer to the figure 1 and the Table 1.
- Rill-Interill Erosion Section
- Gully-Gravity Erosion Selection
- Deposit Section of Channel
This division is very important to remote sensing interpretation and thematic mapping such as soil erosion mapping such as soil erosion mapping, land use mapping, etc., corresponding to the different sections. Particularly, the boundary between rill-interrill erosion section and gully-gravity erosion section which can be portrayed along gully heads can only be precisely identified from color infrared aerial photos (on the scale of 1:10,000-1:50,000). But, on SPOT and TM images, the gullies which are narrower than 5m-10m can not be identified distinctly because of their resolution. So the rill-interrill
Table 1 Types of Land Use and Soil Erosion in Different Sections
| Location |
Slope |
Land Use |
Soil Erosion |
| Hill slope |
150 |
Hill slope field , terrace field |
Rill-interrill erosion |
| Gully slope |
150 -450 |
Uncultivated gully slope land |
Gully -gravity erosion |
| Channel |
50 |
Silt land |
Silt depositing or delivering |
Erosion area portrayed on SPOT or TM images is larger than that on color infrared aerial photos. This would lead to incorrect area measurements of rill-interrill erosion section as well as of gully-gravity erosion section simultaneously. Figure 2 shows the above fact on four kinds of images.
Figure 2 Contrust of the Four kind of Remote Sensing images
