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Black and Red Soils of India

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Black Soil (Regur)

Black soil covers about 16% of India’s area, primarily in the Deccan plateau. It is famously associated with cotton cultivation.

Formation

  • Derived from the weathering of Deccan Trap basaltic lava rocks
  • Formed in situ (residual soil) — not transported by rivers
  • Rich in minerals originally present in volcanic rocks

Distribution

Region Extent States
Central Highlands Largest belt Maharashtra (entire Vidarbha, Marathwada), MP, Gujarat
South-eastern Second belt Telangana, N Karnataka, NW Tamil Nadu
Malwa Plateau Western MP Ratlam, Ujjain, Mandsaur, Bhopal

Characteristics

  • Color: Deep black to dark grey when wet; lighter grey when dry
  • Texture: Clayey — high proportion of clay (40-60%)
  • Moisture retention: Extremely high; swells when wet, shrinks when dry (self-ploughing)
  • Deep cracks in summer — allows aeration
  • Rich in: Calcium carbonate (lime), potash, magnesium, iron
  • Deficient in: Nitrogen, phosphorus, humus

Crops

  • Cotton (prime crop — cotton belt of India)
  • Sugarcane, wheat, tobacco, oilseeds, jowar, gram
  • Does not require irrigation for cotton if monsoon is adequate

Red Soil

Red soils cover about 18% of India’s area, mainly in the Peninsular region.

Formation

  • Formed from weathering of ancient crystalline and metamorphic rocks (granite, gneiss, schist)
  • Red color due to high iron oxide content

Distribution

  • Tamil Nadu, Karnataka, Andhra Pradesh, Telangana, Odisha
  • Eastern MP, Chhattisgarh, Jharkhand, eastern Maharashtra
  • Parts of West Bengal and Bihar

Types

Type Characteristics Location
Red loam Sandy-silty with clay; better fertility Western and central Deccan
Red sandy Coarse texture; poor water retention Eastern and southern parts
Red gravelly Shallow with gravel; low fertility Hilly regions

Characteristics

  • Color: Red to reddish-brown (iron oxide); becomes yellowish when hydrated
  • Texture: Sandy to loamy; well-drained
  • Acidic in nature (pH 5.0-6.5)
  • Rich in: Iron, potash
  • Deficient in: Nitrogen, phosphorus, humus, calcium
  • Porous and friable; easy to cultivate

Crops

  • Millets (ragi, jowar, bajra)
  • Pulses (gram, tur, moong)
  • Oilseeds (groundnut, til)
  • Tobacco, cotton (with irrigation), vegetables
  • Tea, coffee, cashew in hilly areas

Comparison: Black vs Red Soil

Feature Black Soil Red Soil
Color Black to dark grey Red to reddish-brown
Texture Clayey Sandy-loam to clayey
Water retention High Low to moderate
Cracks in summer Deep cracks No significant cracks
pH Alkaline (7.5-8.5) Acidic (5.0-6.5)
Parent rock Basalt (Deccan Trap) Granite, gneiss
Main crops Cotton, sugarcane Millets, pulses, groundnut