Download SOIL - Gyanpedia

• What is Soil?
• **********
• The mixture of rock
particles and humus is
called the soil.
• Soil is one of the most
important natural
resources .It supports the
growth of plants by
holding the roots firmly
and supplying water and
nutrients.
• It is the home for many
organisms.
• Soil is essential for
Agriculture.
• It provides food,clothing
SOIL
SOIL PROFILE
• Soil is composed of
distinct layers.A vertical
section through different
layers of the soil is called
the soil profile.
• Each layer differs in
texture, colour , depth
and chemical
composition.These layers
are referred to as
HORIZON.
A-HORIZON
• A-HORIZON(TOP SOIL)
• *********************
• The uppermost horizon is called A-horizon or top
soil.
• It is dark in colour and rich in humus(the rotting
dead matter in the soil ) and minerals.
• It is fertile and provides nutrients to growing
plants.
• It is generally soft,porous and can retain more
water.
• It provides shelter for many living organisms such
B-HORIZON
• B-HORIZON(MIDDLE LAYER)
• ***************************
• This layer has a lesser amount
of humus but more of minerals.
• This layer is generally harder
and more compact.
C-HORIZON
• C-HORIZON
• ***********
• This layer is made up of small lumps of
rocks with cracks and crevices.
BEDROCK
• BEDROCK
• *********
• This is the innermost layer of the soil
profile.
• It is very hard.
• It is very difficult to dig with a spade as it is
made up of only rocks.
TYPES OF SOIL
• The soil is classified
on the basis of the
particles of various
size.
• It is of three types• 1-Sandy soil
• 2-Clayey soil
• 3-Loamy soil
SANDY SOIL
• If soil contains greater
portion of big particles it
is called as sandy soil.
• Sand particles quite large .
• They cannot fit closely
together,so there are large
spaces between
them.These spaces are
filled with air .
Water can drain quickly
through these spaces .
So, sandy soil tend to be
light ,well aereated and
CLAYEY SOIL
• If the portion of fine
particles is relatively
higher then,it is called
Clayey soil.
• Clay particles being much
smaller,packed tightly
together leaving little
space for air.
• Unlike sandy soil ,water
can be held in the tiny
gaps between the particles
of clay.So clay soils have
little air but they are heavy
as the hold more water
LOAMY SOIL
• If the amount of large and
fine particles is about the
same then the soil is called
loamy soil.
• The best top soil for
growing plants is loam.
• Loamy soil is a mixture of
clay,sand and another type
of soil particles called as
Silt.
• Silt occurs as a deposit in
river beds.The size of silt
particles is between those
of sand and clay.
• The loamy soil has humus
in it.It has right water
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