Soil & Drainage
Soil erosion does not pose any immediate problem in the union
Territory, though sometimes small portions from one part of the islands
get washed away during the south west monsoon and the soils get
deposited in another part. Most of the soil of western shore of Agatti
and Kavaratti has been blown away by the wind and left barren. In some
islands like Minicoy and Agatti, soil has become so shallow that even
lapping of the small wave can uproot the coconut trees. Casuarina,
scaveola, pemphis etc. are planted as second layer to the shore
protection works in some areas to protect soil erosion.
formation of Lakshadweep soil is from fragmentation of coral lime stones and
sedimentary rocks. It is formed by sediments deposited by water and wind which
are consolidated into rocks by weight of the overlying deposits. Later by
fragmentation of the lime stones and sedimentary rocks fine soil is accumulated.
soil tract along the sea shore is white in colour. The soil in the interior
tract of the island generally is ash coloured for the reason that from the
remnants of the plants and animals, inorganic and organic acids are formed which
in turn bring about profound influence on rapid weathering and changes the white
colour of the soil. Calcite is the chief constituent of lime stone and is the
main source of calcium in soil.
typical section of the soil profile:
Horizon A:- This is the upper most layer of the
soil which contain a considerable amount of ash coloured organic matter about 20
cm in thickness. This provides a congenial surface for root foraging of the
Horizon B:- In this, leached products of Horizon A
are deposited. The colour of the soil becomes more and more white according to
the depth and this horizon represent the sub soil.
Horizon C:- This forms the immediate weathered
parent material having texture of unbound soil particles purely white in colour.
IV. Horizon D:- This is the
beneath of the horizon C, where
the solid parent rock material known as PARA is seen.
In the mechanical composition of the soil, the maximum quantum is of coarse sand
followed by fine sand and silt. Clay content is comparatively very little in the
island soil and it is only found in the interior shallow belts. Typically the
soil along the coasts of islands is sandy in nature where only coconut is grown.
In the interior tracts with sandy loam soil, besides coconut, other crops like
Bread fruit, Banana, Anonaceous fruits etc. are coming up well.
The pH of the soil is neutral, the index ranging from 6-8. Generally soil is
rich in Phosphorus and calcium, yet too deficient in the macro elements,
nitrogen and potash. Phosphatic soil with 11 to 24 percent P2 O5 is found in
Kiltan, Chetlat and Kalpeni. Guano reserves accumulated in Pitti is rich in
Phosphorus with round about 18 percent P2 O5. A considerable portion of the
surface soil in the above island is a good reserve of Phosphates.
The soils are dominantly sandy in texture and hence highly porous in nature. In
general, the soils are excessively drained. However the low lying lands
are imperfectly drained. The rainwater moves vertically down and wherever the
substratum of coral limestone is met, move laterally and joins the sea / lagoon.
Of late, because of the human activity, human waste and other pollutants reach
the lagoon and adversely affect the fragile ecosystem, harming the fish and
coral growth around the islands.