The Definition of Soil Erosion
Soil erosion is a natural phenomenon, refers to the earth's surface is constantly affected by wind, water and ice melting. And gradually resulting the surface soil and rock are subjected to various kinds of damage, movement and accumulation.
It is the process that soil and its parent material is destructed、erosed、transported and deposed under the external influence of the hydro, wind, freezing and gravity.
Reasons for Soil Erosion
Natural cause
a.Climate:The precipitation is the direct dynamic and major climatic factor of soil erosion. Rain may move soil directly:'rainsplash erosion'. The rain must fall with sufficient intensity on bare soil to detach and move soil particles a short distance. This is solely an on-site effect. Because rainsplash requires hig hrainfall intensities, it is most effective under convective rainstorms in the world's equatorial regions.
b.Terrain:The surface slope, slope length and shape have an important influence on the soil erosion.
c.Vegetation:Vegetation can fix the ground and slow flow rate.
Artificial causes
a.Destruction of vegetation
b.Unreasonable Farming System
More recently still, the use of powerful aaricultural implements has,in some parts of the world,led to damaging amounts of soil moving downslope merely under the action of gravity: this is so-called tillage erosion.
C.Mining
The Damage of Soil Erosion
1.Reduce the agricultural productivity and (natural landscape) ecological collapse, both because of the loss of nutrient rich upper soil layers.In some cases,the final result is desertification.
2.Erosion removes the topsoil first. Once this nutrient-rich layer is gone, few plants will grow in the soil again.Drought and flood disasters will be more frequent.
3.Without soil and plants the land becomes desertlike and unable to support life.
4. Affect transportation
The Measures of Soil Erosion
Biological measure:Planting windbreaks
Engineering measure:Constructing reservoir and building level terrace.
Agricultural measure:Returning farmland to forests and grasslands and establishing reasonable livestock carrying capacity.