Just like any other organisms, crop-destroying soil microbes die if they get too hot. With that fact in mind, scientists have developed a new system in which soil-heating microwaves are used to kill such pests. The technology could one day replace the use of environmentally harmful pesticides.
Developed by Dr. Sunshin Jung and colleagues at the Korea Electrotechnology Research Institute (KERI), the setup incorporates a proprietary antenna that emits microwaves down into the soil.
By selectively increasing or decreasing the wavelength and phase of those waves, it’s possible to space them in such a manner that they meet and overlap at specific points underground. The amplitude of the waves is increased at those points, causing the moisture in the soil to heat to a temperature of 60 to 100 ºC (140 to 212 ºF) – the exact temperature can be adjusted via the antenna.
In its current form, the system is able to heat soil to a depth of 30 cm (11.8 in). Jung and his team believe that this should be sufficient for eradicating harmful microbes such as bacteria, fungi and nematodes which live on or near plants’ roots – although unfortunately, beneficial microbes would likewise be affected. By contrast, a weed-killing microwave setup developed at the University of Melbourne only reaches down 5 to 10 cm (2 to 3.9 in).
The KERI technology is now in the process of being commercialized by industry partner Jooeun Care Farm Co. It could conceivably also find use in applications such as non-destructively killing termites in wooden structures, melting ice on winter roads, or cleaning oil-contaminated soil.
“We took advantage of the wave nature of microwaves, directing them to superimpose, not spread, and heat the soil underground,” said Jung. “This technology helps to kill pests residing underground after harvest without the use of pesticides, their side effects and environmental pollution, and will contribute a lot to agricultural productivity and farmers’ income.”