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READY RECKONER OF INDIANGEOGRAPHY |30|

Gujarat, Andhra Pradesh and some parts of Tamil and silica are leached away, and soils rich in iron oxide
Nadu. and aluminium compound are left behind.

• These soils are also known as the ‘RegurSoil‘ or the • Humus content of the soil is removed fast by bacteria
‘Black Cotton Soil‘. Generally clayey, deep and that thrives well in high temperature.
impermeable.
• Poor in organic matter, nitrogen, phosphate and
• They swell and become sticky when wet and shrink calcium, while iron oxide and potash are in excess.
when dried. So, during the dry season, these soil Hence, laterites are not suitable for cultivation.
develop wide cracks like‘self ploughing‘.
• Red laterite soils in Tamil Nadu, Andhra Pradesh and
• Because of this character of slow absorption and loss Kerala are more suitable for tree crops like
of moisture, the black soil retains the moisture for a cashewnut.
very long time, which helps the crops, especially, the
• The laterite soils are commonly found in Karnataka,
rain fed ones, to sustain even during the dry season.
Kerala, Tamil Nadu, Madhya Pradesh and the hilly
• Chemically, the black soils are rich in lime, iron, areas of Odisha and Assam.
magnesia and alumina. They also contain potash. But
5. Arid Soils
they lack in phosphorous, nitrogen and organic
matter. The colour of the soil ranges from deep black • Arid soils range from red to brown in colour.
to grey.
• They are generally sandy in structure and saline in
3. Red and Yellow Soil nature.

• Red soil develops on crystalline igneous rocks in areas • They lack moisture and humus. Nitrogen is insufficient
of low rainfall in the eastern and southern part of the and the phosphate content is normal. Lower horizons
Deccan Plateau. Yellow and red soils are also found of the soil are occupied by ‘kankar‘ layers because of
in parts of Odisha and Chattisgarh and in the southern the increasing calcium content downwards.
parts of the middle Ganga plain.
• The ‘Kankar‘ (calcium)layer formation in the bottom
• The soil develops a reddish colour due to a wide horizons restricts the infiltration of water, and as such
diffusion of iron in crystalline and metamorphic rocks. when irrigation is made available, the soil moisture is
It looks yellow when it occurs in a hydrated form. readily available for a sustainable plant growth.

• The fine-grained red and yellow soils are normally • Arid soils are characteristically developed in western
fertile, whereas coarse-grained soils found in dry Rajasthan, which exhibit characteristic arid
upland areas are poor in fertility. topography. These soils are poor and contain little
humus and organic matter.
• They are generally poor in nitrogen, phosphorous and
humus 6. Saline Soils

4. Laterite Soil: • Also known as Usara soils. Saline soils contain a
larger proportion of sodium, potassium and
• Laterite has been derived from the Latin word ‘Later‘
magnesium, and thus, they are infertile, and do not
which means brick.
support any vegetative growth.
• The laterite soils develop in areas with high
• They occur in arid and semi-arid regions, and in
temperature and high rainfall. These are the result of
waterlogged and swampy areas.
intense leaching due to tropical rains. With rain, lime

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