What is Soil Erosion

• Soil erosion is a natural process & remove soil from one location to another. It becomes a problem when human activity causes it to occur much faster than under natural conditions.
• Soil erosion is the detachment, transport & deposition of soil particle on land surface-termed as loss of soil.
• Soil loss is of interest primarily On-site effect of srosion such as loss of crop productivity.
• Off site effect of erosion are siltation in ditches, streams, reservoirs.
• Sediment generated by erosion processes are prime carrier of sgriculture chemicals that pollutes stream or lakes.
• Soil erosion is the washing or blowing away of the top layer of the soil.
• Erosion whether it is by water, wind or tillage, involve three distinct action- soil detachment, movement & deposition.

Soil Erosion Problems

• Soil is the most precious gift of nature- Prime resource- for food, fooder etc.- soil mismanaged- less productivity.
• In India, more than 100 million hectares- soil degraded eroded unproductive.
• Soil erosion deteriorates soil quality & reduces productivity of natural, agriculture & forest ecosystem.
• Soil erosion deteriorates quality of water.
• Increased sedimentation causes reduction of carrying capacity of water bodies.

Solution to prevent Soil Erosion

• Vegetation
• Contour Farming
• Build retaining walls
• Wind Breakers
• Conservation tillage
• Mulching

Mechanics of Erosion

• Begins with raindrops striking bare soil dislodging particles.
• Intense rains seal surface.
• When rainfall exceeds infiltration water is stored in small depressions.
• Once depressions are filled, runoff begins.
• Initially water flows in a discontinuous sheet.
• Eventually it concentrates into small channels or rills.
• The runoff now has energy to break off particles and cut deeper.
• The amount of erosion caused by sheet and rill erosion increased with slope and distance.
• Rills may eventually from gullies.

Types of Soil Erosion

• Normal or geologic erosion occurs under normal natural conditions by itself without the interference of man. It is a very slow process.
• Accelerated soil erosion is the most serious types of loss generally caused by an interference of any agencies like man & animals. It is a rapid process.
• Geological Erosion: Soil forming and distribution- long time process.
• Human and animal: Tillage, removal of plants and Tillage, removal of plants and other vegetation- accelerated erosion.
• Stream bank erosion.
• Landslide, Volcanic eruption, flooding.
• Water and wind: major factors of soil erosion.

What is Erosion Control

• Erosion control is the practice of preventing or controlling wind or water erosion in agriculture land development, river banks, coastal areas, and construction.
• Use land according to its capability.
• Protect the soil surface with some form of cover.
• Control runoff before it develops by an erosive force.

Effect of Soil Erosion

• Loss of Soil: The top-soil is lost by erosion which is the most fertile section, having evolved over centuries of soil forming processes. Due to the formation of gullies & ravines, valuable agriculture lands are lost.
• Harmful effects of soil erosion on organic matter & soil structure: Erosion of upper layer of soil decreases the content of organic matter & as soil nutrients. As a result the soil structure gets improverished.
• Decline in soil capacity: When soil is removed bodily from field, both potential and available plant food along with mineral material is carried away. As erosion progresses, the compact soil of low infiltration capacity is approached. The ability of land to apply moisture for plant growth is reuced and the beneficial activity of micro-organisms lessened. Due to these bad effects, the yield are lowered.
• Deposition of sand & gravel on agriculture lands: The wind-borne sand encroaches the arable lands and makes them unfertile. Crops are damaged due to sand storms.
• Flooding of streams: Soil erosion in catchment areas due to deforestation & other destructive activities leads to silting of streams & reservoirs. This reduces the capacity of these water bodies to carry large volume of waters, as they occur during the rainy season. This way streams are more prone to flooding.

Conclusions

• Soil erosion seems to have substantially decreased upland water storage quantities.
• Lost storage capacities associated with soil loss suggests substantially greater flooding is also likely to occur.
• Soil conservation practices can play important roll in reducing down stream flood losses by lowing flood flows.
• We have only placed a decimal point on erosion impacts on flooding potential; more complex analysis is warranted.