Researchers develop ‘electronic soil’ that improves crop growth

Barley plants grow on average 50% more when their root system is electrically stimulated by a new growing medium. In a study published in the journal PNASResearchers at Linköping University have developed an electrically conductive “soil” for soilless growing, known as hydroponics.

“The world’s population is increasing and we are also facing climate change. It is therefore clear that we will not be able to cover the planet’s food needs with existing agricultural methods alone. But with hydroponics, we can also grow food in an urban environment. environments in very controlled environments”, explains Eleni Stavrinidou, associate professor at the Organic Electronics Laboratory at Linköping University and head of the Electronic Plants group.

His research group has now developed an electrically conductive growing substrate, suitable for hydroponics, which they call eSoil. Researchers at Linköping University showed that barley plants grown in conductive “soil” grew up to 50% more in 15 days when their roots were electrically stimulated.

Hydroponics means plants grow without soil, needing only water, nutrients and something their roots can attach to: a substrate. It is a closed system that allows water to be recirculated so that each plant receives exactly the nutrients it needs. Therefore, very little water is required and all nutrients remain in the system, which is not possible in traditional cultivation.

Hydroponics also allows for vertical growing in large towers to maximize space efficiency. Crops already grown this way include lettuce, herbs and some vegetables. Grains are generally not grown hydroponically except for use as fodder. In this study, researchers show that barley plants can be grown hydroponically and have a better growth rate thanks to electrical stimulation.

“This way we can grow the plants faster with fewer resources. We don’t yet know how this actually works, or what biological mechanisms are involved. What we found is that the plants process the nitrogen more efficiently, but it is not clear. but how electrical stimulation affects this process,” explains Starvrinidou.

Mineral wool is often used as a growing medium in hydroponics. Not only is it not biodegradable, but it is also produced in a very energy-intensive process. eSoil e-Growing Substrate is composed of cellulose, the most abundant biopolymer, mixed with a conductive polymer called PEDOT. This combination as such is not new, but it is the first time that it has been used for growing plants and thus creating an interface for plants.

Previous research has used high voltage to stimulate roots. The advantage of the Linköping researchers’ “ground” is that it consumes very little energy and poses no high voltage danger. Stavrinidou believes that the new study will pave the way for new areas of research to further develop hydroponics.

“We can’t say that hydroponics will solve the problem of food security. But it can certainly help, especially in regions where there is little arable land and environmental conditions are difficult,” she says.