Dryland salinity and rainfall patterns: A preliminary investigation in central west New South Wales (Australia)
2008
Dragovich, D. | Dominis, M.
Dryland salinity is an increasingly serious land degradation problem in many parts of the world. Bare salinised ground leads to accelerated rates of sheet, rill and gully erosion; decreasing plant productivity; and declining surface water quality. In a given geological, climatic and land use situation, rainfall patterns may influence the changing extent of dryland salinity. This possibility was investigated for an area in Australia with long-term rainfall records. Changes in salinisation were recorded using nine sets of aerial photographs. Saline sites fluctuated in size between photo-years but their number and extent increased between 1958 and 1996, with sites along wash lines being especially responsive to rainfall variations. Saline areas generally decreased in size and number during the wet period from 1958 to the early 1970s, extended during drought years in the early 1980s, then increased markedly to 1996 during a period of above average rainfall. Three saline sites showed a broad inverse relationship between salinity (bare ground) extent and rainfall in the pre-drought period but post-drought trends showed increasing rainfall associated with increasing salinisation. Short-term variations in salinity were superimposed on longer-term expansion.
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