Soils of India: Short notes Soil erosion:washing away of the fine and fertile top most layer of the soil cover. Forms of soil erosion: sheet, rill, gully erosion Serious constraint on red soil:sheet erosion Sand dunes are formed by: wind erosion Major consequences of soil erosion:desertification and heavy siltation Contour bunding: soil conservation Tribal people: jhumming or shifting cultivation Average erosion of fine soil per hectare in India:16.4 tonnes The older alluvium soil:Bhangar The New/Younger alluvium soil:Khadar Alluvial soils are formed by river systems through deposition of fine grained sediments Bhangar:more clayey and darker colour Khadar:sandy in texture and light colour Black/Regular/Chernozems soils: Most clayey and moisture retentive capacity Red soils:derived from weathering of crystalline and metamorphic rocks. Absence of lime, kankar and free carbonates Loamy(fertile) in deep depressions. Laterite soils: very poor in fertility Mountain soils:Immature soils Desert soils:formed under arid and semi-arid conditions. Cotton:the most suitable crop of black soils or regular soils or chernzomes. Synopsis: Types of soils: Alluvial soils: these soils are formed by river systems through deposition of fine grained sediments rich in lime and potash, deficit in nitrogen and organic content. Bhangar: older alluvium Khadar(newer alluvium) Black cotton or regular soils(black soils have developed over deccan lavas, gneisses and granites under semi-arid conditions.Tropical chernozems with deep black colour Red soils: derived from weathering of crystalline and metamorphic rocks Absence of lime, kankar and free carbonates Laterite soils:It leads to the leaching away of the much silica from the original rock. These soils are composed of a mixture of hydrated oxides of aluminium and Iron. Mountain soils: these are immature soils.Usually deficient in nitrogen,phosphorous and humus Desert soils:these soils are formed under arid conditions. They include wind blow loess formations.Rich in phosphate content but poor in nitrogen. Types of soil erosion: Sheet erosion: weathering process in the form of layers.this erosion is common in the heavy rainfall areas of shiwaliks, western ghats, eastern ghats, assam and north eastern parts of peninsula Rill erosion: finger shaped grooves(bihar, uttar pradesh, Madhya Pradesh etc) Gullies:Rill may deeper and enlarge:(Banks of the Yamuna,the Chambal and the mai river) Common questions associated: Cotton cultivation mostly favoured in which type of soil?(balck / regular soil) Old Alluvial soil?(Bhangar) New alluvial soil?(khaddar) Erosion caused by heavy rainfall?(sheet) Desert soil rich in?(phosphate content) Soil formed by weathering of metamorphic rock:Red soil
Posted on: Mon, 10 Mar 2014 04:07:55 +0000
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