Technology under development at the University of New South Wales could
offer new hope to farmers in drought-affected and marginal areas by enabling
crops to grow using salty groundwater.
Associate Professor Greg Leslie, a chemical engineer at UNSW's UNESCO Centre
for Membrane Science and Technology, is working with the University of
Sydney on technology which uses reverse-osmosis membranes to turn previously
useless, brackish groundwater into a valuable agricultural resource.

"We are looking at ways to grow plants on very salty water without damaging
soil," Professor Leslie said.

"We're incorporating a reverse osmosis membrane into a sub-surface drip
irrigation system."

The irrigation system relies on the roots of the plant drawing salty
groundwater through the membrane - in doing so removing the salt which would
otherwise degrade the soil and make continued cropping unsustainable.

Desalination such as this requires a pressure gradient to draw clean water
through the membrane. Professor Leslie has demonstrated that, by running
irrigation lines under the ground beneath the plants, the root systems of
the plants provide enough of a pressure gradient to draw up water without
the high energy consumption usually required for desalination.

"We're going to provide agriculture with a tool to grow crops in drought
years when there is limited access to run-off and surface water," he said.
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