With the world’s population growing by the second, experts around the world have reiterated the need to find newer, and more sustainable, ways of doing agriculture to meet the global food demand.
Now, researchers in Sweden have developed an electrically conductive “soil” for soilless cultivation, known as hydroponics. The researchers at Linköping University found that barley seedlings grow on average 50% more when their root system is stimulated electrically through a new cultivation substrate. The findings of their study were published recently in the journal PNAS.
“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,” Eleni Stavrinidou, associate professor at the Laboratory of Organic Electronics at Linköping University, and leader of the Electronic Plants group, says in a press release.
Stavrinidou’s research group calls the electrically conductive cultivation substrate, tailored to hydroponic cultivation, eSoil. The researchers were able to show that barley seedlings grown in the conductive “soil” grew up to 50% more in 15 days when their roots were stimulated electrically.
The substrate is an important part of hydroponics. In hydroponic cultivation, plants grow without soil, needing only water, nutrients and something their roots can attach to – a substrate. According to the press release, it is a closed system that enables water recirculation so that each seedling gets exactly the nutrients it needs. Therefore, very little water is needed, and all nutrients remain in the system, which is not possible in traditional cultivation.
Hydroponics also allows for vertical cultivation in large towers to maximise space efficiency, the release adds. In the past, crops such as lettuce, herbs and other vegetables were grown using hydroponics.
A common cultivation substrate used in hydroponics is mineral wool, which is non-biodegradable and also produced with a very energy intensive process. "eSoil” is made of cellulose, an abundant biopolymer, mixed with a conductive polymer called PEDOT. This combination as such is not new, but this is the first time it has been used for plant cultivation and for creating an interface for plants in this manner, the release explains.
“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,” Starvrinidou explains in the release.
The researchers say their electronic soil has very low energy consumption and does not require high voltage to stimulate the roots, unlike some other such solutions. Starvrinidou believes the study could open the path for new research areas to develop further hydroponic cultivation.