Page 89 - Science Class 07
P. 89
v Habitats for Organisms : Soil provides SOIL EROSION
habitat to millions of ny organisms. It It is a process in which the top fer le layer of
contains both micro fauna and macro soil is lost. Due to soil erosion, the soil becomes
fauna. The micro fauna includes worms, less fer le. The top layer of soil is very light
burrowing insects and arthropods. The which is easily carried away by wind and water.
macro of fauna includes earthworms and The removal of topsoil by the natural forces is
snails. known as soil erosion.
Factors that Increase Soil Erosion
Soil erosion is, however, a slow natural process.
But various ac vi es of man has increased the
rate of soil erosion.
These factors are:
Deforesta on : Humans have taken land from
the forest to cul vate in order to feed the ever-
increasing popula on and to build houses,
industries, etc. Cu ng down of trees on a large
scale for these purposes is deforesta on. The
A mouse near its burrow. roots of trees hold the soil together, thus
preven ng the soil from ge ng uprooted.
v Facilitator for percola on and reten on of
When large areas of the forest are cleared, the
water : Soil is a renewable natural resource
topsoil gets eroded by wind and flowing water.
and play a vital role in composi on of
biosphere. About 50% of soil is made up of
water and gases. It implies that soil
contains ample amount of water. Water
holding capacity of soil helps it to serve as
a reservoir of water. This important
property of water helps to grow vegeta-
on.
A person engaged in cu ng trees.
v A person : When ca les are allowed to
graze on the same field repeatedly, all the
available grass, including the roots are
eaten by them. This makes the topsoil
vulnerable to wind and flowing water,
leading to soil erosion.
v Poor farming methods : Due to poor
farming method the top soil is also washed
Reservoir of Water
Science-7 89
