A “zombie idea” persists no matter how much evidence is presented against it.
A team of scientists, including experts from the University of Adelaide, suggest that reliance on modern irrigation technology as a water-use efficiency strategy is a “zombie idea” – one that persists no matter how much evidence is shown against it.
In an article in Environmental Research Letters, the international research team reviewed more than 200 supporting research articles and found that adopting technology as a water-saving method to improve irrigation efficiency is ineffective and can even exacerbate water scarcity.
“The reason for this is that while water can be saved per acre on a farm, it usually encourages people to bring those water savings back into production, so there is no ‘savings’ in the overall water use equation,” said Co- Author Adam Loch, Associate Professor at the Center for Global Food and Resources at the University of Adelaide.
“It’s an idea that sounds logical, but a closer look at the data shows just the opposite. Investing in water use efficiency can actually increase local water use and contribute to aquifer depletion.
“We have known this for decades, but despite this knowledge, this idea persists and thrives.”
The paper gives several reasons why, despite evidence to the contrary, the idea that modern application technologies (e.g., drip irrigation) conserve water use persists, including beliefs and past decisions that are difficult to reverse.
“We constantly understand the limits of technology, which under ideal conditions can achieve savings of 10-20 percent at best and where saved water is often invested in new productions.” – Associate Professor Adam Loch, Center for Global Food and Resources at the University of Adelaide .
The researchers suggest that some of the key players who continuously support the “zombie idea” are those who sell water-harvesting devices; Politicians who prefer simple popularist solutions; and donor organizations looking for easy investable options instead of dealing with tough and unpopular decisions.
“Some of these groups may find it easy to advocate water-use efficiency, but they don’t have to wear the can if it doesn’t bring long-term savings,” said Associate Professor Loch.
“We constantly understand the limits of technology, which under ideal conditions can only achieve savings of 10-20 percent at best and where saved water is often invested in new productions,” said Dr. David Adamson, co-author of the University of the Adelaide Center for Global Food and Resources.
“Most farmers do not choose to invest in these technologies without financial support such as subsidies because they understand the limitations of these systems and their ability to provide further benefits.”
This result has been consistently observed around the world, and it is a growing problem in arid regions that have tapped their non-renewable fossil groundwater supplies (deep underground water reserves) to sustain agricultural production.
“It is an unfortunate and ‘inconvenient truth’ that modernization, touted as the boom for greater water efficiency, is not saving water in our aquifers or in our rivers,” said Dr. Adamson.
So why are some governments continuing to promote drip irrigation? The authors cite several reasons, including incentives for companies to sell equipment and the fact that farmers genuinely appreciate government subsidies (sometimes up to 90 percent).
“Subsidies can help them switch to higher quality perennials (like almonds) and increase local production without understanding the risk of future water scarcity due to droughts and climate change,” said Dr. Adamson.
“This is great for these farmers in the short term. But it exposes them to greater vulnerability and indebtedness when droughts occur and droughts are likely to occur more frequently in the future. “
Associate Professor Loch said while recent evidence that increased irrigation efficiency tends to increase water use continues to be ignored, future water supply reliability is declining.
“We need to get the message across that modernization and other subsidized investments in irrigation are not the panacea for saving water and maintaining our agricultural production systems for the future.”
In their research, the team outlines a plan for future water-saving interventions. The plan includes properly accounting for water use before and after an intervention to accurately measure savings, working with engineers to better assess modernization limits, and informing downstream users how they will be affected to ensure changes are made are appropriate and positive.
“A willingness to implement these changes during the next shock (e.g. drought), when stakeholders are less resilient to change, can ultimately put this zombie idea to rest,” said Associate Professor Loch.
Reference: “Saving Water in Agriculture Using Technology: A Zombie Idea” by C. Dionisio Pérez-Blanco, Adam Loch, Frank Ward, Chris Perry and David Adamson, Accepted, Environmental Research Letters.
DOI: 10.1088 / 1748-9326 / ac2fe0
