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)