When analyzing the condition of soil whether it is cultivated and chemical-free, there is a fact you know, that, it’s healthy. And healthy soil is alive. Yet, you may not necessarily know how things are going underground as much as the surface. That’s a critical question researchers have also been asking nowadays to clarify. They are trying to investigate the interrelationships in the hidden side of the ecosystem to practice on.
Acoustic emissions are what researchers have been observing for different types of soil structures by using piezoelectric sensors.
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What they have discovered is interesting; when earthworms burrow tunnels, or roots grow, they make a specific noise which shows a meaningful connection back to root and worm activities.
According to professor Dani Or (at the ETH Zurich Institute of Biogeochemistry and Pollutant Dynamics), now they can, for instance, figure out ‘at what time exactly the roots grow‘. As they didn’t know that so far, -if that happened in the day or in the night, or under some circumstances like the humid condition of the soil -, this new method lets them discover the hidden underground life
For the first time in history, those acoustic sensors made it possible to observe biological activity in the soil, as the research proved us.
“Worms have more irregular acoustic emissions than roots, besides they move much faster than roots underground as well”.
Two different soil structure to compare
The visual measurements and acoustic ones were compared to evaluate this hypothesis by comparing two different corn planted soil structures in which earthworms were allowed to burrow their own ways. The divergence of those soils was, while one of them filled with loamy soil, another one was sandy soil-filled glass cells.
According to the recorded acoustic emissions, which were sent in the form of 1-100kHz frequency wawes by piezoelectric sensors, those sound waves were generated when small grains of soil rub against each other by the movements of worms – which is impossible to be heard by humans.
Researchers waited for 1 week for the worms to burrow and 19 days for the roots to grow. Recorded sound results created by both worms and roots, that they found out after this long observation were highly coherent.
Benefits of analyzing the condition of soil structure is not limited to this
The benefits of this research, according to Dani Or, are the outputs he could get from the acoustic sounds. He learned to discriminate a wide range of acoustic sound signals. He already achieved to examine early signals of landslides – which is a life-saving advance. Although the single sound signal itself has a very low value, a bunch of them can lead us to some important clues and sources.
As the professor claims, this new approach to soil analysis
According to Or, in the future, farmers, (and it means gardeners too) might benefit this new advancement alongside other means of soil analysis studies.