Soil erosion which means the removal of soil particles by the natural agents of transport like wind, water and ice. Majorly, the soil erosion is occur by the water agent. The erosion by water is of two forms: sheet erosion and gully erosion.
1)Sheet Erosion:-Rainfall on an artificially made soil, especially on gently sloping fields,generally results in sheet erosion. In this process, many soil grains are pounded loose and made free to float away during the initial stages of the rainfall. This process starts simultaneously over a large area so that after some time during the rains, a huge thick sheet of water flows down slope gaining acceleration and hence greater capacity of further erosion of soil underneath.
sheet erosion will result in uniform skimming of top soil. Sheet erosion is very dangerous because it may not leave any trace of erosion.
2)Gully Erosion:- This signifies formation and evolution of downslope valleys, often in multitudes, that develop on sloping soil covers due to continued soil erosion. Gullying is in fact consequence of sheet erosion. Uniform sheet erosion
over any surface for longer periods is not possible even on perfectly smooth surfaces. The rate of erosion along different paths would be different creating conditions for excessive concentrated erosion along some paths. These path of excessive erosion eventually develop into gulleys with the passage of time.
1)Sheet Erosion:-Rainfall on an artificially made soil, especially on gently sloping fields,generally results in sheet erosion. In this process, many soil grains are pounded loose and made free to float away during the initial stages of the rainfall. This process starts simultaneously over a large area so that after some time during the rains, a huge thick sheet of water flows down slope gaining acceleration and hence greater capacity of further erosion of soil underneath.
sheet erosion will result in uniform skimming of top soil. Sheet erosion is very dangerous because it may not leave any trace of erosion.
2)Gully Erosion:- This signifies formation and evolution of downslope valleys, often in multitudes, that develop on sloping soil covers due to continued soil erosion. Gullying is in fact consequence of sheet erosion. Uniform sheet erosion
over any surface for longer periods is not possible even on perfectly smooth surfaces. The rate of erosion along different paths would be different creating conditions for excessive concentrated erosion along some paths. These path of excessive erosion eventually develop into gulleys with the passage of time.
Methods to control Soil Erosion:- Methods adopted to prevent and control soil erosion is classify into two sections: agronomic and engineering practices.
By Agronomic Practice is understood protection of the top soil by special methods and schemes of crop cultivation. these include:
1)Crop Rotation:-In which the different crops are grown in the same area by rotation, that is one after another. A sequence commonly followed is a cultivated crop, a small grain and then grass. after this cultivated crop may again sown.
2)Strip Cropping:-In which the cultivated crops and the cover crops are sown in alternate strips during the same period in the same field.
The Engineering Methods most widely used for combating soil erosion include:
a)Excavation of ditches- These can be described as artificially created channels excavated at suitable locations to divert the excess of water approaching the affected areas, especially in steeply sloping regions.
The ditches have to be designed carefully so that erosional velocities are not develop in them.
b)Terraces Construction:- These are constructed along suitable location across the slope of hillsides with essential function of collecting the runoff to an erosion proof outlet.
c)Check Dams:- Small check dams constructed out of various materials like stones, timber and steel etc. have been found especially useful in combating gullying. Such dams serve the purpose of reducing the velocity of runoff and cause deposition of the material which may ultimately support vegetation.
By Agronomic Practice is understood protection of the top soil by special methods and schemes of crop cultivation. these include:
1)Crop Rotation:-In which the different crops are grown in the same area by rotation, that is one after another. A sequence commonly followed is a cultivated crop, a small grain and then grass. after this cultivated crop may again sown.
2)Strip Cropping:-In which the cultivated crops and the cover crops are sown in alternate strips during the same period in the same field.
The Engineering Methods most widely used for combating soil erosion include:
a)Excavation of ditches- These can be described as artificially created channels excavated at suitable locations to divert the excess of water approaching the affected areas, especially in steeply sloping regions.
The ditches have to be designed carefully so that erosional velocities are not develop in them.
b)Terraces Construction:- These are constructed along suitable location across the slope of hillsides with essential function of collecting the runoff to an erosion proof outlet.
c)Check Dams:- Small check dams constructed out of various materials like stones, timber and steel etc. have been found especially useful in combating gullying. Such dams serve the purpose of reducing the velocity of runoff and cause deposition of the material which may ultimately support vegetation.
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