Since European settlement, the condition of our soil has been significantly changed by poor understanding of environmental processes and land management practices such as vegetation clearance, grazing, cultivation, the introduction of exotic soil flora and fauna and the application of fertilisers, herbicides and pesticides. This meant that after vegetation was cleared, soils were exposed to erosion by wind and water, stripped of nutrients and salinised.

Land uses have evolved over the years, with large areas of highly productive land have been alienated from agriculture by urban sprawl, and extensive agricultural practices being replaced by increasingly intensive and productive practices and industries. Land use in areas closer to towns and settlements is generally more intensive, involving greater modification to the natural environment. Generally, the more intensive the land use, the greater the potential impact on the environment and the greater the need to sustain the capacity of those resources.

Soil erosion and acidity are two of the most significant problems that have resulted from agricultural land management practices. Soil loss and acidification permanently reduce the productive capacity of agricultural lands, and can adversely affect water resources and biodiversity.

Rates of soil acidification and the area of affected land continue to increase in most agricultural areas, while rates of soil erosion have declined somewhat, although not nearly to a level that will ensure long-term sustainability.

Dryland salinity is also a considerable problem. Salt is a natural feature of the Australian landscape. Until European settlement this salt remained deep in the soil, below the root zone of native vegetation. This deep-rooted native vegetation tended to use most of the rainfall that it received; little rainfall percolated down to the underlying groundwater.

However, since settlement, large areas of native vegetation have been cleared for agriculture and replaced with shallow-rooted annual crops and pastures which has significantly disrupted the natural balance. Shallow-rooted crops and pastures do not use as much rainfall, so excess rainfall tends to seep down through the soil profile.

While in the short term the extent of dryland salinity in South Australia is relatively stable, the processes set in train many years ago as a consequence of vegetation clearance mean that we are likely to see further increases in the area affected, particularly in the regions adjacent to the River Murray. It is predicted that without on-ground action, such as revegetation and drainage to intercept it, groundwater will slowly drain towards the River, significantly increasing its salinity into the future.