Research on land Resource by Remote Sensing in inner Mongolia, China
This method was checked by sampling test and its error is 4.97 – 5.03%, therefore, it is suitable for this study.
4. Combining image processing with visible interpretation and combining the previously mentioned approaches together can improve classification accuracy concerning the identification of sand and saline land, irrigated land and meadow, deteriorated grassland and different levels of desertification land.
5. The visual interpretation is a main method, in particular, geoscience analysis and ecological analysis are important.
Results and Discussions
1. The percentage of area for various land use forms of Inner Mongolia Autonomous Region is as follows: Cultivated land 6.0%, rangeland 55.47%, forest and woldland 15.89%, water surface 1.27%, settlement and mining area 0.56%, desert 16.58%, and the rest 4.19%.
the percentage of various grassland types is as follows : meadows steppe 8%, typical steppe 38%, desert steppe 13%, desert 27%, meadow and marsh 14%
The area of deteriorated accounts for 35.57%, and the area of serious deteriorations 19.69%.
2. The problem of land degradation Some of the important natural characteristics in this area, are drought, unreliable rainfall, windy weather and so on. The coverage of vegetation and biomass are relatively low and ecosystems change easily. In addition, the production in this region has been influenced by historical immigration, which results in the frequent change of land use types. So, large area of land is degraded due to unreasonable utilization.
According to the cause and characteristics, we divided degradation into four types.
1 Soil erosion
Based on the data of vegetation community, vegetation coverage and characteristics of soil erosion obtained from Landsat imagery and field work, it is clear that the area of total detiorated pastures is very large, being 74.05% of the total region. There are three types of soil erosion: water-erosion 23.59%, wind erosion 64.57% and freeze-thaw erosion 11.84% (table 1,2)
Water loss and soil erosion is a serious problem in the southern part, especially in the loess hills and platforms.
Generally speaking, soil erosion is caused by overgrazing and unsuitable management. In the northern part of Inner Mongolia, a large area of pastures have not been utilized due to the lack of water supply. Therefore, the livestock, have concentrated on the beaches along the rivers, around the wells, lakes and residential spots. As a result these pastures have been deteriorating because of overgrazing. Also, some pastures have been ploughed for corps. With the influence of wind erosion, productivity has been decreased to a large extent.
2 The desertification of land
The decertified land is mainly distributed in Hulun Buir, Horgin, Hunshandake, Ordos, and the western part of Inner Mongolia. Surface soil has been eroded by strong wind and sand layer underneath has been exposed. With the change of climate in Quaternary period, many lakes were getting smaller and rivers often changed their ways, which resulted in so large an area covered by alluvial and lacustrine sand deposit which supplied sand in the course of land desertification. In addition, human activities, such as unsuitable ploughing, mining have accelerated land desertification.
3 Salinization and Alkalization of soil
In arid and semiarid region of China, widespread saline and alkaline soils are widely spreaded. In addition, owing to unreasonable irrigation in mang regions, secondary salinization offen occurs on lange area of land. There are 31635km2 salt-affected soil in Inner Mongolia making up 2.78% of the total area. In Hetao Irrigation area, there were only 40000 hectares of saline and alkaline soils and 1958, but increased to 210000 hectares in 1973.
Table 1 Main indices of soil erosion grades
Table 2 Percentage of soil erosion types and grades
| Grade |
1 |
2 |
3 |
4 |
5 |
6 |
Total |
Water erosion (%)
Wind erosion (%)
Freeze-thaw erosion(%) |
9.79
8.75
7.42
|
8.08
18.11
4.43
|
2.87
16.32
4.43
|
1.55
9.50
|
0.56
4.84
|
0.14
7.04
|
23.59
64.57
|
4Rangeland deterioration overgrazing and unbalanced utilization in different has led to rangeland deterioration over an area of about 213000km2, accounting for 35.57% of the whole area. In recent years, livestock husbandy has been developing. The intensity of land use has been increasing. The capability of pasture land has decreased from 0.87 has/(Sheep.a) to 3.3ha/(sheep.a).
Suggestions for pasture management
According to the results of investigation mentioned above, we can conclude that the degradation of land in this area is mainly caused by unreasonable utilization in recent decades. Under the water conditions of this area, the degraded land can be recovered as long as suitable measures are carried out.
1 To develop production, grasslands should be protected and pastures should be improved.
2 Some unsuitable farm land should be changed into pasturel to protect soil from wind erosion.
3 The pastures lacking water should be developed and equipped with water pipes, deep wells, etc.
4 Herbage should be planted in suitable areas to meet the need of livestock for feeding in winter and spring season.
References
Editorial committee of series resources Maps of Inner Mongolia’s Autonomous Region Series Resources Maps of Inner Mongolia Autonomous Region, Science Press, Beijiing, China, 1991.
Zhao Ji, 1990, Research on land degradation in Xilin Gold League, Inner Mongolia by Remote Sensing. Proceeding of the International Symposium on Grassland Vegetation, Science Press, Beijing, China.
Schowengert, R.A. 1983, Techniques for Image Processing and Classification in Remote Sensing, New York.
Townshend, J.R.G. 1981, Terrain Analysis and Remote Sensing, London.
Chen shupen, Developing and Application of Remote Sensing information in China, “Recent Development of geographical Science in China, Science Press, Beijing, China 1990.
