Researchers at Linköping University have created a special electrically conductive soil for growing plants without traditional soil, using a method called hydroponics. The new electrically conductive soil is called ‘eSoil’. The findings of the new study were published on December 25 in the journal Proceedings of the National Academy of Sciences (PNAS).
Hydroponic cultivation is a method to cultivate plants without a soil. Instead, plants grow in a solution that includes all the needed 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.
Mineral wool is often used as cultivation substrate in hydroponics. A wool-like synthetic material made of molten mineral rocks that is not only non-biodegradable, it is also produced with a very energy intensive process. The electronic cultivation substrate eSoil is made of cellulose, the most abundant biopolymer, mixed with a conductive polymer called PEDOT.
Hydroponics usually use electric stimulation for the roots to improve the growth and productivity of plants.
Previous research has used high voltage to stimulate the roots. But the advantage of the Linköping researchers’ soil is that it has very low energy consumption and no high voltage danger.
The Linköping University researchers have shown that barley seedlings grown in the conductive soil grew up to 50 percent more in 15 days when their roots were stimulated electrically.
Hydroponics 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. 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.
“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,” said lead author Eleni Stavrinidou of Linköping University.
“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,” she added.
