Perennials reverse dryland salinity at Boorowa

Perennial pastures have reduced recharge at
Boorowa, on the NSW south-west slopes.

Farming systems have direct influence on the control and mitigation of dryland salinity, according to research carried out in the southwest slopes of NSW by the NSW Department of Primary Industries (DPI).

Recent analysis of long term data from a site at Boorowa by NSW DPI hydrologist, Dr Russell Crosbie, has shown that converting farmland from annual cropping to perennial pastures with tree belts has had a significant effect on the hydrology of the site.

In particular, use of perennial pastures has reduced recharge of water to below measurable levels.

Runoff has also been significantly reduced and the amount of salt being exported out of the 120 ha sub- catchment has been halved.

NSW DPI Technical Specialist (Salinity Management), David Mitchell, said the findings were good news for the Boorowa site, however he cautioned against generalising to other locations.

“Other NSW DPI research shows that land use changes can have a negative impact on stream salinity because reduced water flow can result in less fresh water entering streams.

“There are trade-offs to be made between salt levels and surface water runoff.

“Before undertaking land use changes to combat dryland salinity, it is important to have a good understanding of the processes which cause salinity in a particular location”, he said.

The Boorowa site is one eight sites being studied across NSW as part of the Key Sites project, which is a long-term study of water and salinity movement and the impacts of land use change.

Further information

David Mitchell, NSW DPI, Orange on 02 6391 3852 or david.mitchell@dpi.nsw.gov.au.

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