A study suggests that a small device powered by wind and rain can boost crop yield, but other researchers have cast doubt on the findings
13 January 2022
A team of researchers claims to have shown that a high-voltage electric field generated using wind and rain can boost crop yield, but other scientists say the results should be treated with caution.
The effectiveness of using electric fields to stimulate crop growth, known as electroculture, is far from established, despite being tested in Europe, the US and China. A “golden age” is dawning for the technology, one Chinese scientist told New Scientist in 2019.
Now, Jianjun Luo at the Chinese Academy of Sciences in Beijing and his colleagues have grown two sets of peas in a greenhouse, one of which was exposed to an electric field. Previous tests have drawn electricity from the grid to create the field, but Luo’s one used a small device – a triboelectric nanogenerator – to generate it from wind and rainfall.
The result: pea yields increased by almost a fifth, and the plants germinated faster than the control peas too. “The main advance is that the self-powered system can boost crop yield by harvesting the wasted wind and raindrop energy in our daily life,” says Luo.
He says the generator system they used cost less than $40. The team writes that the approach could be “immediately and widely applied” to increase food production and curb agricultural pollution. Still, Luo concedes that public attitudes to food grown this way could be an issue. “The barriers to rolling this out for commercial food production may be the cost and food safety.”
Ellard Hunting at the University of Bristol, UK, says what is really new here isn’t growing crops with an electric field but using rain and wind power to provide the electricity to do it. That could remove one barrier to electroculture: the carbon emissions and cost of energy consumption. “You could also achieve this with wind turbines and solar panels, but their approach is cheaper,” says Hunting.
Jean Yong at the Swedish University of Agricultural Sciences says while the engineering is novel, the way the experiment was conducted means the researchers have limited biological data on the plants. “It cannot lead them towards providing an explanation for increasing yield or cutting pesticides,” he says.
Luo suggests that the mechanism for how electric fields might increase yield could be photosynthesis, based on his analysis showing the peas under the electric field had more chlorophyll. But exactly how electric fields affect crops remains unclear. “That’s the big question, and nobody really knows,” says Hunting.
There may be other explanations for why the peas exposed to an electric field grew faster. The trial wasn’t “double-blinded”, so the technicians growing the plants knew which were in an electroculture.
The wider problem with electroculture is that a 2018 systematic review of studies looking at how electric fields affect seed germination and plant growth found that all the studies suffered from methodological flaws.
Sarah Driessen at RWTH Aachen University in Germany, who worked on that review, says one of her main concerns with the new study is how overly confident it is that electroculture works. “The authors represent it as a fact that static electric fields promote seed germination and plant growth, although this is highly debatable,” she says. “The authors do not elucidate the current state of knowledge on this topic properly and the basis for their hypothesis is rather poorly supported.”
Journal reference: Nature Food, DOI: 10.1038/s43016-021-00449-9
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