Research suggests reliance on modern irrigation technologies is a 'zombie' theory
A team of scientists, including experts from the 成人大片, suggest that reliance on modern irrigation technologies as a water-use efficiency strategy is a 鈥榸ombie idea鈥 鈥 one that persists no matter how much evidence is thrown against it.
In a paper in听, the international research team reviewed more than 200 supporting research articles and found technology adoption as a water-saving method for improving irrigation efficiency is ineffective, and can actually worsen water scarcity.
鈥淭his is because, while water may be saved per hectare on a farm, it typically encourages taking those water savings and putting them back into production, thus there are no 鈥榮avings鈥 from the total water use equation,鈥 said co-author Associate Professor听, at the 成人大片鈥檚听Centre for Global Food and Resources.
鈥淚t鈥檚 an idea that sounds logical, but a hard look at the data shows just the opposite. Water-use efficiency investments can actually increase local water consumption and contribute to aquifer depletion.
鈥淲e鈥檝e known this for decades, but despite such knowledge this idea persists and flourishes.鈥
The paper identifies several reasons why, in the face of contrary evidence, the idea that modern application technology (e.g. drip irrigation) saves water consumption persists, including beliefs and prior decisions that are hard to reverse.
鈥淲e continually fail to understand the limitations of technology, which at best may only achieve a 10-20 per cent saving under ideal conditions, and where saved water is often placed into new production."听Associate Professor Adam Loch, Environment Institute member.
The researchers suggest, some of the key players who continually support the 鈥榸ombie idea鈥 include those who sell water-use efficiency equipment; politicians who prefer simple popularist solutions; and donor organisations who want easy investable options, rather than dealing with hard and unpopular choices.
鈥淚t may be easy for some of these groups to champion water-use efficiency, but they don鈥檛 have to carry the can when it fails to deliver real savings long-term,鈥 said Associate Professor Loch.
鈥淲e continually fail to understand the limitations of technology, which at best may only achieve a 10-20 per cent saving under ideal conditions, and where saved water is often placed into new production,鈥 said Dr David Adamson, co-author from the 成人大片鈥檚听Centre for Global Food and Resources.
鈥淢ost farmers don鈥檛 choose to invest in these technologies without financial assistance like subsidies because they know the limits of these systems and their capacity to permit further benefits.鈥
This result has been consistently observed around the globe, and it鈥檚 a growing concern in arid regions that have tapped their non-renewable fossil aquifer supplies (deep underground reserves of water) to maintain farm production.
鈥淚t鈥檚 an unfortunate and 鈥榠nconvenient truth鈥 that modernisation, touted as a boom for greater water efficiency, isn鈥檛 saving water as far as our aquifers, or indeed our rivers are concerned,鈥 said Dr Adamson.
So, why do some governments continue to promote drip-irrigation? The authors suggest several reasons, among them corporate incentives to sell equipment and the fact that farmers genuinely appreciate the subsidies (as much as 90 per cent in some places) provided by governments.
鈥淪ubsidies may help them switch to higher-value perennial crops (like almonds), and increase local production without understanding the risk of future water scarcity due to droughts and climate change,鈥 said Dr Adamson.
鈥淭hat鈥檚 great for these farmers in the short-term. But it exposes them to greater vulnerability and debt when droughts occur and droughts are expected to become more frequent in the future.鈥
Associate Professor Loch said while the recent evidence that increased irrigation efficiency tends to increase water consumption continues to be ignored, the reliability of future water supply is declining.
鈥淲e need to spread the word that modernisation and other subsidised investments in irrigation, aren鈥檛 the silver bullet to conserving water and sustaining our agricultural production systems into the future.鈥
In their research, the team outline a plan for future water-saving interventions. The plan includes properly accounting for water use before an intervention as well as after it to measure savings accurately, engaging with engineers to better appreciate modernisation limits, and informing downstream users of how they will be affected to ensure changes are reasonable and positive.
鈥淔inally, being ready to implement these changes during the next shock (e.g. drought), when stakeholders will be less resistant to change, may finally put this zombie idea to rest,鈥 Associate Professor Loch said.
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