Soil salinity
From Freepedia
Soil Salinity is a major environmental issue in Australia, chiefly affecting agricultural lands in many areas of W.A. (Western Australia)
Much of central Australia was at one time a shallow inland sea. This means that in the thin, dry soil there is a layer of saline soil. Prior to 1788, the bush forest above this soil ensured that the soil remained dry, and that the layer of saline soil did not rise. The advent of land clearing for grazing and farming, and the use of irrigation created a much wetter soil environment. Food and industrial crops, while requiring a much larger water usage, also required a much wetter soil environment. This wetness leached down into the saline layers of soil, and the crops then drew the water, and dissolved salts, towards the surface.
Over time this process caused the thin top-soil layers to become irreversibly salty, and no longer suited for agriculture. Large amounts of land are now affected by salinity. Where the land is not yet a salt-pan it is occasionally possible for farmers to reduce the speed at which land becomes saline by planting gum trees, which reduce the general wetness of the soil. Varieties of the saltbush plant, such as Atriplex amnicola, are also useful in these areas, and can help to support livestock.
The CSIRO and many other organisations are seeking ways to reduce the impact of salinity on Australian agriculture.
See also
External links
- Australian Bureau of Statistics 2004 Year book
- Department of the Environment and Heritage
- National Dryland Salinity Program
