COUNTRY
Uganda
SCHOOL
Duhaga Boys Primary
UGANDA
SUBJECT
Integrated Science
TOPIC
Environmental Degradation
SUB –TOPIC
Types of Environmental Degradation
OBJECTIVES
By the end of the lesson pupils should be able to:
Know what is meant by environmental degradation
Mention the types of environmental degradation
Describe how land degradation is caused
DURATION
1 hour
CONTENT
Introductory Phase
Review what are living things and non-living things and define environment. For
instance people use these things to live comfortable lives e.g. we kill animals for
food, cut trees for timber, clear forests or swamps for settlement, farm land and
industries. Emphasize that when the environment is harmed or polluted, the
environment is then said to be “degraded”
Experiencing Phase
Environmental degradation is the condition whereby the quality, usefulness and
stability of the environment is reduced or destroyed by human activities. This leads
to destruction of plants and animals on planet earth. It limits human ability to meet
the basic needs as well. It reduces soil fertility; make the water dirty and the air
unhealthy.
Types of environmental degradation
1)
2)
3)
4)
5)
Soil or land degradation
Deforestation or de-vegetation
Wetland degradation
Pollution of air, water and soil
Wild life destruction
Land degradation is mainly caused by the following:1) Bad agriculture practices for example over cultivation, over grazing and land
fragmentation due to population pressure.
2) Mining, construction and excavation is another kind of land degradation
Mining of Minerals from the ground leads to soils degradation, and
destruction of Vegetation around the Mining site. Here the top soils are
removed until the Mineral ore is reached. Construction in Wetland also leads
to land degradation.
3) Soil removed from building sites and dumped into Valleys and swamps .The
soil covers swamp vegetation and affects the flow of the water in the area.
4) Natural factors such as leaching and soil erosion
5) Materials that reduce the soil value can be plastic and polythene bags or
buvera ,metal scraps and chemical wastes from industries The soil mixed
with plastic objects is not good for agriculture .Plastic or polythene
materials hinder the flow or water and mineral salts in the soil. Even some
micro-organisms that fix nitrogen into the soil are cut off. In such
conditions the soil loses its fertility.
6) Chemicals from industries spoil the soil texture, fertility and add poisonous
chemicals into the soil. Polluted soil of this nature cannot produce good
crops.
Explain the following important terms related to soil degradation
Leaching is the process through which mineral salts or nutrients sink deeper into
the soil layers where they cannot be reached by plants. This may be caused by rain.
Soil erosion is the washing away of topsoil or blowing away the fertile soil.
Over cultivation is another kind of land degradation. This is the frequent use of
land without a period of resting.
This is common in areas where there is land is Scarce.
Overgrazing is also a form of land degradation. This form of soil degradation occurs
when the number of animals is more than the grass can support.
Water disposal: poor disposal of wastes causes soil degradation. The waste damped
on the soil affects its fertility.
Evaluation Phase
1)
2)
3)
4)
5)
6)
7)
8)
Define environmental degradation
State five types of environmental degradation.
What causes leaching?
What is meant by soil erosion?
State two bad agriculture practices.
What is meant by over grazing?
What effect do polythene bags do to the environment?
Of what danger is waste disposal to the soil?
N/B- The teacher will give structured notes on the causes of land degradation
AUTHOR
KAHUMA SARAH (Mrs.)