Barley seedlings grow on average 50% more when their root system is stimulated electrically through a new cultivation substrate. In a study published in the journal PNAS, researchers from Linköping University have developed an electrically conductive "soil" for soilless cultivation, known as hydroponics.
"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. But with hydroponics we can grow food also in urban environments in very controlled settings," says Eleni Stavrinidou, associate professor at the Laboratory of Organic Electronics at Linköping University, and leader of the Electronic Plants group.
Her research group has now developed an electrically conductive cultivation substrate, tailored to hydroponic cultivation, that they call eSoil. The Linköping University researchers have shown that barley seedlings grown in the conductive "soil" grew up to 50% more in 15 days when their roots were stimulated electrically.
Hydroponic cultivation means that plants grow without soil, needing only water, nutrients and something their roots can attach to—a substrate. It is a closed system that enables water recirculation so that each seedling gets 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 enables vertical cultivation in large towers to maximize space efficiency. Crops already being cultivated in this manner include lettuce, herbs and some vegetables. Grains are not typically grown in hydroponics apart for their use as fodder. In this study the researchers show that barley seedlings can be cultivated using hydroponics and that they have a better growth rate thanks to electrical stimulation.
"In this way, we can get seedlings to grow faster with less resources. 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," says Starvrinidou.