New irrigation technique halves water use

A new irrigation technique developed by Commonwealth Scientific and Industrial Research Organisation (CSIRO) could cut the amount of water used by grapevines and other crops in half.

The technique, known as partial rootzone drying, will allow growers to produce grapes – and, possibly other horticultural crops – with significantly less water, according to Dr Brian Loveys, CSIRO Plant Industry.

Partial rootzone drying was developed by Dr Loveys with Dr Peter Dry from the University of Adelaide and Dr Michael McCarthy from the South Australian Research and Development Institute.

Trials have shown that the new irrigation technique actually improves the quality of grapes and their end-product, wine.

“Partial rootzone drying has no effect on yield and can even improve grape quality, while reducing water use by up to 50 per cent,” says Dr Loveys. “The technique uses two irrigation drip lines instead of a single drip line,” said Dr Loveys. “It will work on existing vines with a slight modification to the irrigation system.”

The scientists have found that watering only one side at a time causes biochemical changes in the vine, which reduces the amount of water the plant needs. Because only half the plant’s rootzone is wetted, each watering uses only about half as much water without any loss in terms of yield.

“The partial watering also reduces unwanted foliage on grape vines – which growers normally have to prune away anyway – and grapes grown using the system in trials have turned out to be of slightly better quality,” Dr Loveys says.

Partial rootzone drying has been successfully tested by scientists and growers with grapevines and tests on citrus and some fruit trees also show highly promising results. The work is supported by the Grape and Wine Research and Development Corporation and the Land and Water Resources Research and Development Corporation.

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