"Electronic Soil" Boosts Hydroponic Growth Rates by 50 Percent, Say Scientists

Researchers from Sweden's Linköping University, Lund University, the Swedish University of Agricultural Sciences, and the Foundation for Research and Technology have come up with a way to boost growth in hydroponic gardens — by enhancing the soil-free cultivation method with an "electronic soil" material.

"The world population is increasing, and we also have climate change. So it’s clear that we won’t be able to cover the food demands of the planet with only the already existing agricultural methods," says Eleni Stavrinidou, associate professor at Linköping University and leader of the Electronic Plants group responsible for the project of the issues the team set out to solve. "But with hydroponics we can grow food also in urban environments in very controlled settings."

Hydroponic cultivation grows plants without soil, attaching the roots to a substrate material and providing them with water and nutrients in a tightly-controlled closed-loop system — offering increased efficiency over traditional agriculture, and the potential to create "vertical farms" which require far less land. Boost how well hydroponic crops grow, and those efficiency gains increase too — to the point where it becomes possible to grow grains, as well as vegetables, cost-effectively.

That's where the team's "electronic soil" comes in. Dubbed "eSoil," the material replaces the mineral wool usually used as a substrate in hydroponics with a cellulose-PEDOT mixture. This, the team explains, is electrically conductive, which allows the grower to take advantage of earlier research into boosting growth rate through electrical stimulation of barley seedlings without having to use excessive power or high voltages — improving the growth rate by 50 percent in a 15-day test.

"In this way, we can get seedlings to grow faster with less resources," Stavrinidou explains. "We don’t yet know how it actually works, which biological mechanisms that are involved. What we have found is that seedlings process nitrogen more effectively, but it’s not clear yet how the electrical stimulation impacts this process. We can’t say that hydroponics will solve the problem of food security. But it can definitely help particularly in areas with little arable land and with harsh environmental conditions."

The team's work has been published in the Proceedings of the National Academy of Sciences (PNAS) under open-access terms.

Main article image courtesy of Thor Balkhed/Linköping University.