7. Red soils have two broad classes:
a) Red loam with cloddy structure and
allow content of concretionary
materials; and
b) Red earths with loose, Permeable
top soil and a high content of
secondary concretions. Generally these
soils are light textured with porous
and friable structure and there is
absence of lime Kankar and free
carbonates. They have neutral to acidic
reaction and are deficient in nitrogen
humus, phosphoric acid and lime.
8.
9. 3) Black soils
These are mostly clay soils and form deep cracks
during dry season. An accumulation of lime is
generally noticed of varying depths. They are
popularly known as “Black cotton soils” because
of their dark brown colour and suitability for
growing cotton. These are also known as Indian
regurs.These soils are deficient in nitrogen,
phosphoric acid and organic matter but rich in
calcium, potash and magnesium.
10.
11. 4) Alluvial soils
These soils occur along rivers and represent
the soil materials that have been deposited
by the rivers during flood. Usually they are
very productive soils but many are deficient
in nitrogen, humus and phosphorus.
12.
13. These are mostly sandy soils that occur in
the low rainfall track. They are well
supplied with soluble salts but are low in
nitrogen and organic matter and have a
high pH value. These are quite productive.
These are often subjected to wind erosion.
14.
15. Clay is a fine-grained soil that combines one or
more clay minerals with traces of metal oxides and
organic matter. Geologic clay deposits are mostly
composed of phyllosilicate minerals containing variable
amounts of water trapped in the mineral structure. Clays
are distinguished from other fine-grained soils by
differences in size and mineralogy. Silts, which are fine-grained
soils that do not include clay minerals, tend to
have larger particle sizes than clays. There is, however
some overlap in particle size and other physical
properties, and many naturally occurring deposits
include both silts and clay.
16. Plants get water from the soil where they
grow in. If the soil can hold water, plants
will grow well. But, if the soil is not able to
retain, plants will either die or will need
frequent watering.
Ability of soil to hold water depends on the
following two factors:
17. The amount of water absorbed by a
particular type of soil is called its water
water aborption tenency. Higher is the
water absorption tendency, higher is the
number of plans.
18. The time duration for which water is
retained in the soil is called the water
rentention tendency. Both these factors are
important for plants to absorb water from
soil.
