Calcareous soil , Origin, Properties and Distribution in India (IGKV RAIPUR , C.G.)

1. CALCAREOUS SOIL ORIGIN,
PROPERTIES AND DISTRIUTION

2. INTRODUCTION
• Calcareous is an adjective meaning “mostly or
partly composed of calcium carbonate “ in other
words ,containing lime or being chalky.
•Calcareous soil are soils in which a high amount
of calcium carbonate dominates the problems
related to agricultural land use.

3. CONTINUE....
• They are characterised by the presence of
calcium carbonate in the parent material and by
a calcic horizon ,a layer of secondary
accumulation of carbonates ( usually calcium or
magnesium) in excess of 15% calcium carbonate
equivalent and at –least 5% more carbonate than
an underlying layer.

4. ORIGIN AND FORMATION OF
CALCAREOUS SOIL:-
• Calcareous soil is formed in arid as well as
humid region. It is more common in arid areas .
In dry regions ,calcareous soil is formed in-situ
whereas, it has secondary origin in water logged
area.

5. CONTINUE.....
• (A) Formation of calcareous soil in situ by weathering of
parent rock materials:-There is formation of calcium
carbonate due to weathering of rocks. The low rainfall in
arid and semi- arid regions , is not sufficient to leach out
the soluble products of weathering to ground water. In
dry weather, the salt moves up with the water by
capillary movement to the surface where they are
deposited.
• (B) Development of calcareous soil by secondary origin:-
Calcareous soil of secondary origin is developed in low-
lying areas or in basin shaped areas .Generally drainage
is impeded in these lowlying areas . During the rainy
season , soluble calcium bicarbonate of nearby areas
accumulate in the lowlying areas. During dry season,
calcium bicarbonate converted into calcium carbonate
and deposited on the soil surface by capillary
movement.

6. CONTINUE.......
• The source of primary carbonate minerals in
most soils is marine limestone or dolomite
limestone deposits.
• Carbonate parent materials are mineralogical
quite uniform ,varying only in the presence and
quantity of cation other than Ca and in clay
content.
• Soil development on calcareous parent material
is controlled by the dissolution , re-precipitation
, and leaching of carbonates and their products.

7. PROPERTIES OF CALCAREOUS SOIL
• Calcareous soils mainly contains calcium
carbonate in free form and magnesium
carbonate may remain present in small quantity.
• There is effervescence when calcareous soils
come in contact with the acid (Hcl ).
• Soil colloids contain about 90% calcium and
magnesium carbonate as absorbed bases.
• Calcareous soils are sometimes referred to as
alkaline ( high ph) soils, but they are
distinguishable from other soils with high ph.

8. CONTINUE.....
• Calcite and aragonite ,dolomite and magnesite are
the calcium and magnesium carbonate minerals
found in calacareous soil.
• They are mainly present as calcite , and to lesser
extent as dolomite.
• The ph range of calcareous soils( determined in
water) is from 7.0 to 8.5.
• (A) Physical properties of soil:-
• Calcareous soils remain in a flocculated
condition(granulated). Soil is permeable to water
and air due to large number of pore spaces.

9. CONTINUE.....
• Flocculation in heavy (clay) soil increases pore
spaces and consequently drainage but in light
(sandy) soil it decreases water holding capacity.
• (B)Availability of nutrients:-
• 1. Phosphorous- In calacareous soil , the solubility of
phosphorous is depressed which results in the
decrease of P availability.
• 2. Potassium- Availability of potassium is decreased
due to presence of excess calcium carbonate.
• 3. Zinc- Availability of zinc is reduced.

10. • (C) Activity of microorganism:-
• Moisture is essential o microorganism activity .
Microorganism activity in wet calcareous soil is
normal but it is affected in dry calcareous soil.
DISTRIBUTION
• The calcareous soils in India are located in eastern
Uttarpradesh and north Bihar .
• In Bihar ,calcareous soils are found in Muzaffarpur ,
Darbhanga , Saran , Champaran and Munger district
of north bihar.