krishigyan Published: 3 years ago




Alluvial Soils

  • Most fertile soil
  • grey or greyish-brown in color
  • Texture:- sandy loam to clay loam
  • recent originated soil
  • largest area occupied i.e 75 mha
  • P & K are in sufficient amount
  • pH:- 7.0 to 8.0
  • Found in Bihar, Rajasthan, Punjab, U.P and W.B

Red soils

  • Red due to presence of oxides of iron
  • texture:- light, porous structure, deficiency of organic matter
  • pH:- 6.0 to 7.5
  • parent material:- granite
  • Rich in Kaolinite (1:1)
  • Tamilnadu has largest area of red soil

Black soils (Vertisols):

  • these are generally rainfed
  • clay content:- 40-69% sometimes 80%
  • Local name:-  Regur or Black cotton soil,
  • pH:- 7.5-8.5
  • cover 24% of total area(74m)
  • deficient in nitrogen & phosphorus
  • rich in potash & lime
  • found in Gujrat, Rajasthan, U.P, A.P, Maharastra, M.P and Madras
  • base exchange capacity is quite high

Desert soils (Arid Soils)

  • contain large amount of soluble salts
  • high pH
  • highly found in Rajasthan, range of kutch and south punjab

Laterite and lateritic soils (Ultisols)

  • Deficient: lime ,P, K, Ca, Zn,B etc
  • Texture:- Loamy or clayey
  • pH:- 5.0 to 6.0
  • Oldest or most weatherest

Saline and Alkaline soils:

  • Poor drainage
  • Saline soils are called alkali soil and cause Boron toxicity
  • Its highest percentage is in U.P
  • pH:- more than 8.5

Important Points:-

  • A+B horizon= Solum
  • A+B+C= Regolith
  • Soil Salinity tolerance:- Barley>wheat>beans>upland rice
  • Most abundant mineral on Earth:- Feldspar
  • Most resistant mineral on Earth:- Quartz
  • Most abundant soil in India:- Alluvial soil
  • Maximum Anion exchange capacity:- Kaolinite
  • Minimum Cation exchange capacity:-  Smectite
  • Maximum Cation exchange capacity:-  Montmorillonite
  • Maximum Microorganism in soil:-  Bacteria
  • Water logged soils have more Denitrification
  • For reclamation of acidic soil lime is used
  • For reclamation of alkaline soil Gypsum or Sulphur is used.
  • Soil best for irrigation:-  Red Soil
  • At field capacity maximum moisture is available to plants.
  • C:N ratio for common soil:- 10-12:1
  • No. of master horizons for soil:-5
  • Muriate of Potash is the fertilizer which is not produced in India.
  • In arid and semi-arid regions Alkali soils are found.
  • Maximum saline and alkali soil found in U.P
  • Total essential nutrients- 17
  • Recently “Ni” is added.
  • Most abundant among soil fauna:- Protozoa
  • Ultra micro nutrient – Molybdenum