LAND FORMS & SOIL - PART 4
SOIL EROSION
• Soil-erode-when topmost fertile layer of the soil become loose and gets eroded/washed away with the action of wind or water.Common Causes--Deforestation-Over-grazing-Action of wind, water, glacier, etc.-Faulty methods of agriculture, over-irrigation, shifting agriculture, wrong ploughing, etc.-Other anthropogenic factors(mining activities,industrial activities,etc).
CAUSES OF SOIL EROSION IN INDIA
1) Heavy population pressure on land:
• forest cover as low as 20.55% of total area
• population continues to rise at a rapid rate
• more forests are destroyed
• heavy pressure on land.
2) Nature of Rainfall:
• receives 80 to 90 per cent of rainfall in the monsoon season.
• heavy downpour during during monsoon months causes floods.
• remaining months –droughts –these affect soils.
3) Overgrazing
• number of domestic animals, esp cattle highest in world
• cattle freely graze in open lands making them bare of vegetation
• winds carry away dry soil particles –Rajasthan
4) Bad farming techniques
• plough fields in traditional ways
• small size of holdings, absence ofterracing, contour cultivation, crop rotation, improper use of manure have caused erosion
5) Topography –North –Eastern parts of India, Shiwaliks and the hilly regions in south India are affected by soil erosion because of steep slopes and heavy rainfall. During heavy rainfall, soils are washed away by running water down the slope.
6) Deforestation: destruction of forests for cultivation –cutting of trees exposes the soil to water and wind which leads to soil erosion
REGIONS OF SOIL EROSION : Rajasthan, Madhya Pradesh, Maharashtra, UP, Gujarat, Andhra Pradesh, Karnataka.
Worst affected areas include:
• The badlands of Chambal and Yamuna rivers
• The piedmont zone of the western Himalayas
• The Chotanagpur plateau region
• The Tapi-Sabarmati valley region in Gujarat
• The regur soil area of Maharashtra
• The dry areas of Rajasthan, Gujarat and Haryana
EFFECTS OF SOIL EROSION:
• Loss of fertile top soil
• Lowering of the underground water table and decreasing soil moisture
• Drying of vegetation and extension of arid lands, increase in the frequency of droughts and floods
• Silting of river and canal beds, Recurrence of landslides, adverse effect on economic prosperity and cultural development
• Wind erosion reduces the productive capacity of soil, as mostof the nutrients required by the plants are carried by the wind.
PREVENTION OF SOIL EROSION
1. Terrace Farming: On hilly slopes, terraces act as bunds and prevent the soil from being washed away.
2. Contour ploughing: Ploughing along contourson a slopeprevents soil being washed away by rainwater or by surface run off. Contours act like bunds. Terraces are levelled into step like small fields with even slope.
3. Afforestation: planting of trees along the edges of the fields, the waste land and on steepy slopes to prevent soil erosion as wellas to enahnce the capacity of the soil to retain water.* increase area under forests and indiscriminate felling of trees must stop.
4. Shelter Belts: Farmers plant trees in several rows to check wind erosion. Known aswind breaks.
5. Strip cropping: Crops are grown in alternate strips of land to check the impact of the winds.
6. Construction of dams: Rivers cause soil erosion. Dams are built in the upper course of rivers to control erosion of soil. This would check the speed of water and thereby save soil from erosion.
7. PloughingGullies: The gullies made in the soil are plugged with deposition of silt during heavy rains.
8. Shifting or Jhuming or slash and burn typeof agriculture should be banned.
• Soil-erode-when topmost fertile layer of the soil become loose and gets eroded/washed away with the action of wind or water.Common Causes--Deforestation-Over-grazing-Action of wind, water, glacier, etc.-Faulty methods of agriculture, over-irrigation, shifting agriculture, wrong ploughing, etc.-Other anthropogenic factors(mining activities,industrial activities,etc).
CAUSES OF SOIL EROSION IN INDIA
1) Heavy population pressure on land:
• forest cover as low as 20.55% of total area
• population continues to rise at a rapid rate
• more forests are destroyed
• heavy pressure on land.
2) Nature of Rainfall:
• receives 80 to 90 per cent of rainfall in the monsoon season.
• heavy downpour during during monsoon months causes floods.
• remaining months –droughts –these affect soils.
3) Overgrazing
• number of domestic animals, esp cattle highest in world
• cattle freely graze in open lands making them bare of vegetation
• winds carry away dry soil particles –Rajasthan
4) Bad farming techniques
• plough fields in traditional ways
• small size of holdings, absence ofterracing, contour cultivation, crop rotation, improper use of manure have caused erosion
5) Topography –North –Eastern parts of India, Shiwaliks and the hilly regions in south India are affected by soil erosion because of steep slopes and heavy rainfall. During heavy rainfall, soils are washed away by running water down the slope.
6) Deforestation: destruction of forests for cultivation –cutting of trees exposes the soil to water and wind which leads to soil erosion
REGIONS OF SOIL EROSION : Rajasthan, Madhya Pradesh, Maharashtra, UP, Gujarat, Andhra Pradesh, Karnataka.
Worst affected areas include:
• The badlands of Chambal and Yamuna rivers
• The piedmont zone of the western Himalayas
• The Chotanagpur plateau region
• The Tapi-Sabarmati valley region in Gujarat
• The regur soil area of Maharashtra
• The dry areas of Rajasthan, Gujarat and Haryana
EFFECTS OF SOIL EROSION:
• Loss of fertile top soil
• Lowering of the underground water table and decreasing soil moisture
• Drying of vegetation and extension of arid lands, increase in the frequency of droughts and floods
• Silting of river and canal beds, Recurrence of landslides, adverse effect on economic prosperity and cultural development
• Wind erosion reduces the productive capacity of soil, as mostof the nutrients required by the plants are carried by the wind.
PREVENTION OF SOIL EROSION
1. Terrace Farming: On hilly slopes, terraces act as bunds and prevent the soil from being washed away.
2. Contour ploughing: Ploughing along contourson a slopeprevents soil being washed away by rainwater or by surface run off. Contours act like bunds. Terraces are levelled into step like small fields with even slope.
3. Afforestation: planting of trees along the edges of the fields, the waste land and on steepy slopes to prevent soil erosion as wellas to enahnce the capacity of the soil to retain water.* increase area under forests and indiscriminate felling of trees must stop.
4. Shelter Belts: Farmers plant trees in several rows to check wind erosion. Known aswind breaks.
5. Strip cropping: Crops are grown in alternate strips of land to check the impact of the winds.
6. Construction of dams: Rivers cause soil erosion. Dams are built in the upper course of rivers to control erosion of soil. This would check the speed of water and thereby save soil from erosion.
7. PloughingGullies: The gullies made in the soil are plugged with deposition of silt during heavy rains.
8. Shifting or Jhuming or slash and burn typeof agriculture should be banned.
SOIL CONSERVATION SCHEMES
1. The centrally sponsored scheme of Integrated Watershed Management in the catchments of flood-prone rivers was launched during sixth Plan in eight flood-prone rivers of the Gangetic Basin covering seven States and one Union Territory. It aims atenhancing the ability of the catchment by absorbing larger quantity of rainwater, reducing erosion and consequent silt load in the stream and river beds and thus helping to mitigate the fury of floods in the productive plains.
2. A scheme for reclamation and development of ravine areas was launched in 1987-88 in MP, UP and Rajasthan. –included prepheral bunding to halt further ingress of ravines, afforestation of ravines, aforestaton of ravines for fuel, fodder and reclamation of shallow ravines.
3. Control of shifting cultivation is implemented since 1994-95 in the States of Arunachal Pradesh, Assam, Manipur, Meghalaya, Nagaland, TripuraThe integrated programme envisages settling of families practising shifting cultivation.it helps them to practise terraced cultivation, raising of horticultural palantations and afforestation to support animal husbandry and to meet fuel and fodder requirements.
4. In urban areas, rain water harvesting is means of checking soil erosion, besides recharging ground water.
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