Boosting recycled water use for agriculture

New research to expand the use of water recycling for irrigating South Australia’s vineyards has been initiated by the Australian Water Recycling Centre of Excellence.

Led by the South Australian Research and Development Institute (SARDI) and co-funded by the Goyder Institute for Water Research, the project is collaborating with the local viticulture industry and the University of Adelaide to demonstrate the economic and environmental value of water recycling to Australia’s agrifood industry.

In announcing the project, Australian Water Recycling Centre of Excellence CEO Dr Mark O’Donohue said the security of water supply is an ongoing concern for producers of horticulture crops.

“Recycled water can provide a secure, climate-resilient water supply for many agricultural areas of Australia. This project will contribute to a growing body of knowledge about how to incorporate the use of recycled water into a variety of irrigation regimes,” said Dr O’Donohue.

Project investigator Tim Pitt, from SARDI, said, “The project involves crops being watered under very precise irrigation systems and looks at how to mitigate the salt content of recycled water by diluting it with fresh rainwater. We will be applying recycled water to vineyards in the McLaren Vale [region] and to almond orchards on the Northern Adelaide Plains.”

The trials at a McLaren Vale vineyard, owned by Treasury Wine Estates, will test whether redirecting rainfall - from raised soil mounds built between the vines to soil directly under vines irrigated with recycled water - reduces the build-up of salt. Preliminary studies indicate that redirecting rainfall run-off to drip lines can reduce the salt content in vine leaves and grapes by 20 to 30%.

The almond orchard trials will use mixtures of recycled water and freshwater to identify the most salt-sensitive growth stages of almonds. Such knowledge will have value to producers, water utilities and policy makers trying to maximise the use of recycled water in agribusiness.

“We will also assess how the changing concentrations of salt, in the various soils being assessed, affect plant response in terms of vigour, yield and crop quality,” said Pitt.

Based on the success of the trials, the horticulture industry could expand its use of recycled water schemes for precision crop irrigation in other dry regions and improve management of soil salinity.