The subject has become so important that institutions such as the US National Science Foundation are allocating millions to research the use of cold plasma in agriculture in the form of beams emitted in temperature-controlled rooms.

The proliferation of new projects would be all too familiar to those who practiced a strange obsession in the 19th century: electroculture, a technique that involved applying electricity to plants to make them produce better flowers, leaves and fruit, or even get rid of them. from parasites, but the results were always mixed. This new generation of researchers is abandoning the word “electroculture” in favor of terms like “smart agriculture” or “fourth agricultural revolution”. However, the mechanism in the “Basics” section remains the same, and proponents agree that after centuries of failure, using electricity for plants may finally bear fruit. It is hoped that these futuristic systems can be used to combat the global food crisis by reducing the environmental impact of large-scale agriculture. According to the 2005 estimate. , various components of agriculture can account for 10 to 12% of greenhouse gas emissions. greenhouse effect every year.

The production of synthetic fertilizers from the energy-intensive Haber-Bosch process, which revolutionized agriculture in the early 20th century, today produces hundreds of millions of tons of carbon dioxide (CO2) per year. Soil erosion due to unregulated land use increases Therefore, many researchers of the new wave of electric agriculture believe that their technique can play a role in improving food production.

To increase yields, some scientists are returning to inventions inspired by the “electrovegetometer” created by a French physicist in the 1780s. It was a kind of lightning rod that provided crops with atmospheric electricity, often with undesirable consequences.

In the United States, several institutions are trying to revive the artificial lightning approach, however, when ancient electrocultivators first tried to take advantage of it centuries ago, their questionable anecdotal results were the only support for the method’s implementation. Lightning strikes both damaged plants and encouraged them. However, since the last century, it has been possible to apply these rays with greater precision. This is done using plasma, a substance created naturally by lightning that is extremely hot. usually several million degrees, and which turns into a kind of ionized gas. New technologies allow us to manipulate it at room temperature, then we are talking about cold plasma. Its use is an “extremely active area [dans l’agriculture] right now,” says José López, a Seton Hall University professor who also served as director of the US National Science Foundation’s (NSF) Plasma Physics Program.

Together with biochemist Alexander Volkov of Oakwood University, Alabama, they are among those who have embraced the growing trend of applying cold plasma to new seeds in various forms. Volkov observed in his experiments a yield increase of 20 to 75%, depending on the plant. “We increased cabbage production by 75%. The cabbage also tasted better. The flavor, he says, was milder. These scientists aren’t the only ones .

Some studies have reported a variety of benefits that plasma brings to crops, from faster and larger plant growth to greater resistance to pests. “As far as we know, plasma works by waking up the seed,” says Lopez. When the seeds germinate, that’s when the new plant is most vulnerable to various environmental “stressors”. So she refuses to open up until she is “satisfied” with her surroundings. Speeding up this process has been a common practice in agriculture for a long time, although it is usually achieved by chemical agents such as acids. Plasma seems to do the same thing, but much more efficiently. “It pierces the seed wall, and when you plant it, it has a greater ability to absorb water and soil,” Lopez says. “After a few seconds of treatment, the plant grows faster than untreated seeds. The plasma even seems to revive plants that have already grown,” says Mr. Lopez, whose own group at NSF has used a precision instrument called pencil plasma to treat. sweet basil plants. These plants became stronger and healthier, and their mass and height increased by 20%. “The results are remarkable,” says Mr. Lopez.

While scientists aren’t yet entirely sure how it works, particularly how electricity interacts with whole plants, they currently have several NSF-funded initiatives to find out.

This uncertainty explains why there is still skepticism about the use of electricity in agriculture. Some argue that 200 years after the first Victorians unsuccessfully electrified their perennials, it is still unclear how electricity interacts with their biology. “We’ve known for decades that electric fields promote plant growth,” says Sena, of the Plant Morphogenesis Laboratory at Imperial College London. The problem is that these data have never been completely reproduced because the experiments have been carried out under variable conditions. However, to make electrical intervention in plants a technologically valid method, it is useful to understand its scientific basis. Deciphering the molecular mechanism behind a plant’s response to an electric field is at the heart of work carried out by Sena’s group at Imperial. They particularly focus on electrical research. signals internally generated by plants. These organisms send countless signals at every stage of their growth and in every part of their anatomy, which can be measured using a variety of instruments. Identifying these signals could help scientists know what the plant needs, whether it’s water or a pest. food or even soil, at each stage.

Unlike other needs, it is not possible to simply create more land. For a long time, the best answer to this problem was the promise of vertical farming, which would allow crops to grow on any surface. There’s just one problem, Sena says. What we call vertical farming is a misnomer. We do not grow plants vertically, but we stack narrow boxes vertically that grow horizontally. This is because the roots are not vertical. Roots obey the law of gravity. They look for water and look “down”. This makes it very difficult to grow multi-rooted plants in space. In the absence of gravity, the roots move in all directions, which makes it logistically difficult to feed them properly. What if vertical farming literally did what the name implies? What if it were possible to grow fruits and trees with roots that extend lengthwise instead of downward? Roots grow downward because the living organism senses the pull of the gravitational field and the presence of water and coordinates its tissues to follow that direction. But that’s not the case. all roots can perceive. They also have the ability to detect electric fields, a sense that can override all others. The electric field has veto power over the roots’ response to the gravitational field.

Last year, Salvalaio and Sena showed for the first time in precise molecular detail how to use specific doses of electricity to reorient the direction of root growth in an Arabidopsis plant.

In other words, they grew it the way they wanted. That’s why these cubes look delicious. Salvalaio and Sena collaborated with the Dyson School of Design Engineering in London to develop special 3D-printed hydrogel cubes that can house growing Arabidopsis plants. , as well as electrodes that will guide the growth of their roots in a lateral position. The bright green leaves clearly show that the air tunnels create an enriching environment. Its roots curl tightly. Salvalaio plans to go electric this summer. If all goes well, to say ‘the sky’s the limit’ would be an understatement.” The ability to control the direction of root growth would mean we could grow trees from the roof as well as from the wall.” , Sena explains. Thanks to this new electrical advancement, it would even be possible to grow trees in a weightless environment. There could be trees on the International Space Station or forests on the moon.