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Soil degradation and desertification Ashish(2011A22BIV)
SOIL DEGRADATION AND
• Soil degradation is the decline in soil quality
caused by its improper use, usually for
agricultural, pastural, industrial or urban
• The Decline in quantity and quality of soil It
includes Erosion by wind and water Biological
degradation (loss of humus) Physical
degradation (loss of structure, permeability,
compaction) Chemical degradation (reduced
fertility, salinisation , changing pH, toxicity)
If Degradation is so severe that land becomes
unusable it is termed desertification
• Desertification is a process of turning the
productive land into desert.
• A definition of desertification should recognize
that it is a land degradation process that
involves a continuum of change, from slight to
very severe degradation of the plant and soil
resource, and is due to man's activities.
• Desertification is also a situation on the desert
expansion. That means desert is continuously
expanding to the surrounding area.
Causes on desertification
Poor / poverty
↓ Soil fertility ,↓ soil degradation &↓ Soil aridity
land and timber for cropping & building,
cutting down to tree extensively.
Over cropping—-∵demand for food
crops↑ & the cash crops demanded ↑,
↑shifting cultivation, ↓soil fertility,
infiltration >E underground water table
Global warmingCO2↑, T ↑, ice cap
melt, flooding in coastal area , ↓ rainfall,
drought , veg. die
Less rainfallDrought , veg. die.
“If the climatic factors are said to be the
main causes of desertification ,then
human activities are going to intensify it.”
Effects on desertification
-loss of arable
-land intensify the
Upset the balance of ecosystem
1)loss of arable land
soil texture change to sandy ↓cohesive power
(cannot hold water) not suitable for veg growth
2)intensify the soil erosion
1.↑ deforestationno root to bind the soil
↑ soil erosion↑ silting
1)Water cycle breaks down
∵↓Rainfall & ↑ evaporation(∵ no
rivers and wells dried up
1)lower the bio-diversity
↓R” & unevenly dis.+deforestation
scattered veg. (veg. Is shorter, few
species, less luxuriant)extinction
1)lower the income
Rainfall ↓ crops productivity
2)use a large amt of capital for soil
protection & recovery
How to solve???
1.Control the pop. growth / natural increase
by using family planning, in order to
decrease the land use capacity
2.The number of grazing and the rate of
cultivation should not over the carrying
capacity of land
How to solve???
3. Improve i)farming & ii)grazing methods,
in other to reduce soil erosion and
i) suitable timing and amount to carry out irrigation
plant the halophytes (which can adapt salty &
droughted soil) e.g, Chenopodiaceae
ii)sufficient fallowing period
How to solve???
4.Legislation: band the deforestation and over
grazing, etc. , in order to balance the ecosystem
5.afforestation i.e. plant the wind break trees &
drought resistant plants
7. Building reservoir and canal , (e.g, The Indira