Always outspoken about the threat of salinity, John Williams, Deputy Chief of CSIRO Land and Water, told the Queensland State Landcare and Catchment Management Conference that our current farming system, based on annual crops and pastures, doesn’t fit our ancient, dry continent.
Instead, what is needed is a new landscape with a mosaic of tree crops, mixed perennial-annual cropping systems, and significant areas devoted to maintaining ‘the bush’ so as to retain landscape function.
“In reality, only extensive or complete revegetation with native or other plants that have similar groundwater recharge rates will reduce groundwater to preclearing levels,” he says. “In most situations this is unlikely to be the management goal.”
Trees for all seasons?
Radical change to land use will involve the development of commercial tree production systems for large areas of land that are presently used for crops and pastures, according to Dr Williams.
These would include trees to produce fruits, nuts, oils, pharmaceuticals, bush foods and forestry products such as specialty timbers, charcoal and biomass energy.
He stressed that ‘ecosystem services’ are the unsung and undervalued components of the landscape that underpin all communities by providing clean water and fertile soil.
Danger in the north
Dr Williams also told the conference that the north of Australia was not immune to salinity. He said there is sound scientific evidence to suggest that, with continued clearing, there is danger of dryland salinity in very large areas of the semi-arid summer rainfall zones of Queensland and the Northern Territory.
“We need a substantial new research effort on landscape renewal to redesign farming and forestry systems and their integration into the Australian landscape as a whole,” says Dr Williams. “This will have to take into account economic and social issues as well as land and climate considerations.”