Major
Causes of Land Degredation
Land degradation
is any change in the condition of the land which reduces its productive
potential. This includes the loss of topsoil, the loss of vegetation
and increasing soil salinity.
The degradation
of agricultural and pastoral land in Australia is a matter of considerable
concern.
Factors that
have contributed to land degradation include:
- soil erosion
- loss of
soil fertility
- soil structure
change
- salinisation
- soil pollution
- desertification
- loss of
vegetation cover
- introduced
herbivores such as rabbits and goats
- increases
of populations of native herbivores such as kangaroos
- overuse
of irrigation water.
Land degradation
from human activities has the following effects:
- causes
deterioration in the chemical and physical properties of soils
- accelerates
soil loss
- reduces
primary productivity of plant communities
- results
in a decline in biodiversity
- leads
to increased hazards for human occupancy.
Impacts of land degradation
Land-degradation
impacts are felt by the agricultural industry. Thus the economic
and social effects of land degradation are felt most by the people involved
in agriculture. For example, in relation to soil, in the short term
the economic and social effects may come from the reduced capacity of
the soil to sustain plant growth for crops or pasture, resulting in reduced
yields.
Most agricultural
practices lead to natural vegetation being replaced by plants more suited
to the agricultural systems. This occurs either through direct clearing
and replacement of native vegetation by overgrazing, by changes in water
availability and salinisation, or simply by the failure of the native
species to recruit new individuals to replace those that die. Although
land clearing was seen as essential to grow food and fibre, it has opened
our land resource to damage by erosion, destroyed soil structure and changed
soil chemistry and caused a loss of biodiversity and other problems.
(Source:
TAFE Queensland and Department of Natural Resources Module ASP3056:
Environmental Impacts: Issues, 1999)
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