Saving water a waste?



irrigation in farming

Credit: iStockphoto

- Advertisement -

SYDNEY: Measures to conserve water in irrigation may actually increase overall water usage, new research from North America suggests.

While using an irrigation method more efficient in water usage considerably reduces water needed for farming, it actually increases overall water use, report researchers from New Mexico State University in the US and the Technical University of Valencia in Spain.

"Our findings suggest re-examining the belief widely held…that increased irrigation efficiency will relieve the world's water crisis," wrote researchers Frank Ward and Manuel Pulido-Velazquez in the journal Proceedings of the National Academy of Sciences.

The duo, who used mathematic modelling of water use in North America's Upper Grande Rio Basin, have come up with a finding that seemingly flies in the face of conservation logic.

They highlight an apparent downfall in water conservation policy, which encourages farmers to use efficient irrigation practices, saying that increased water efficiency in agriculture - the world's largest user - will not free up water for environmental uses, as is the widespread belief.

Instead, it will lead to irrigators investing the water they save back into producing higher crop yields on greater acreages.

Large scale problem

The researchers analysed water use in 'drip irrigation', a farming measure widely believed to conserve water, and which is being increasingly used in Australia's own Murray-Darling Basin.

Drip irrigation allows water to be supplied precisely where it is needed - at the root area of a plant - rather than being spread all over huge areas of farming land ('flood irrigation').

In theory this sounds good - and indeed, depending on the crop, about half the amount of water is needed for drip irrigation compared with flood irrigation, the researchers said.

Single page view