Soil erosion is the detachment and transportation of soil material from one place to another through the action of wind, water in motion or by the hitting action of the rain drops.
•When the vegetation is removed and land is put under cultivation the natural equilibrium between soil building and soil removal is disturbed.
•The removal of surface soil takes place at a much faster rate than it can be built up by the soil forming process.
Erosion by water: Known as water erosion, is the removal of soil from the lands surface by water in motion.
Sheet erosion: The removal of a thin relatively uniform layer of soil particles by the action of rainfall and runoff.
•Usually so slow that the farmer is not conscious of its existence
•Common on lands having a gentle uniform slope
•Results in the uniform removal of the cream of the top soil with every heavy rain
•Shallow top soil overlies a tight sub soil are most susceptible to sheet erosion
•Movement of soil by rain drop splash is the primary cause of sheet erosion
•Sheet erosion has damaged millions of hectares of slopping land throughout the India
Rill erosion is the removal of soil by running water with the formation of shallow channels that can be smoothed out completely by normal cultivation.
•There is no sharp lines of demarcation where sheet erosion and rill erosion begins but rill erosion is more readily apparent than sheet erosion.
•Rills develop when there is a concentration of runoff water which, if neglected, grow into large gullies.
•More serious in soils having a loose shallow top soil.
•Transition stage between sheet erosion and gul-lying.
Gully erosion: Removal of soil by running wa-ter with the formation of channels that cannot be smoothed out completely by cultivation.
•Advance stage of rill erosion.
•Any concentration of surface runoff is a poten-tial source of gullying.
•Cattle paths, cart tracks, dead furrows, tillage furrows or other small depression down a slope favour concentration of flow.
•Unattended rills deepen and widen every year and begin to attain the form of gullies.
•Unattended gullies may result over a few years for an entire landscape to be filled with a net-work of gullies.
•More spectacular than other type of erosions.
Stream channel erosion: Erosion caused by stream flow.
•Closely resembles rill erosion.
•Intensive channel erosion areas are on the outside of lands where flow shear stresses are high.
Mass movement: Enmass movement of soil.
•Landslides, land slips, soil and mudflows are various forms of mass movement.
Wind erosion: Movement of soil particles is caused by wind force exerted against or parallel to surface of the ground.