Soil Science

by Sanjit sen (Editor)

Soil is defined as the naturally
occurring, unconsolidated mineral
or organic material at the surface
of the earth that is capable of
supporting plant growth. Soil is
synonymous to the word 'earth',
the word from which our planet
derives its name. Here are some
quick facts about soil.

Types of Soil: Clay, silt and
sand are the three types of
soil. Most soils are a blend of
all three types. The texture
and appearance of soil
depends on the content of
each of these. Sand is mainly
granular and is composed of
rock particles and minerals.
Clay has fine-grained minerals
and high water content. Silt is
a granular material derived
from rock. It may occur as a
deposition in water. Silt is also
known as stone-dust.

Composition of Soil: Soil holds
0.01% of the Earth's water. Soil
is a composition of 49%
Oxygen, 33% Silicone, 7%
Aluminum, 4% Iron, and 2%
Carbon. Air and water make up
50% of the soil. Minerals and
organic matter make up the
rest.

Formation of Soil: Soil
formation is a lengthy process.
Soil forms by the process of
physical or chemical weathering
of rocks. Microorganisms in the
soil help in breakdown of
organic matter in the soil.
Decaying of plants and animals
helps in the formation of soil.
Earthworms recycle nutrients
thus making the soil richer.

Layers of Soil: The topmost
layer of soil is called topsoil. It
contains high amounts of
humus and microorganisms.
Biological activity occurs most
in this layer. It is from this
layer that plants derive their
nutrients. Not much humus is
present in the layer below this
layer. The process of leaching
brings down the minerals from
the upper layers to the layers
below. The bottom-most layer
consists of withered rock.

Some Interesting Facts about Soil
Soil influences many areas of
our lives. It is an integral part
of our ecosystem. The
composition of the soil in an
area has a direct effect on the
plant and animal life there.
It takes more than 500 years to
form 2 centimeters of topsoil.
Ten tons of topsoil spread
evenly over one hectare of land
comes out to be as thick as one
Euro coin.
A fully functional soil holds
3750 tons of water per hectare,
thus reducing the risk of
floods. It holds pollutants to a
certain extent. Soil stores
around 10% of the emissions of
carbon dioxide.
Just one gram of soil contains
5000 to 7000 different species
of bacteria. A spoonful of soil
can hold a substantial amount
of living beings.
Scientists have found 10,000
types of soil in Europe and
about 70,000 types of soil in
the United States.
75% of the earth's crust is
composed of silica and oxygen.
Soil is a non-renewable natural
resource. This should make us
think of how much we value
this resource. Damage to the
soil can disturb nature's
balance and prove a threat to
life.

122 pages, Kindle Edition

First published September 24, 2014