For decades, Japanese farmers have associated naturally occurring lightning strikes from storms with increased mushroom harvests. In fact, through the years lightening strikes became an integral part of Japanese farming lore — a belief that bountiful mushroom harvests always follow thunderstorms.
This long held legend prompted researchers at Iwate University in northern Japan to conduct a four-year study of artificially inducing electrical bursts on a variety of lab mushrooms to determine if electricity makes the fungi multiply.
Ten varieties of mushroom were tested, and eight responded favorably by growing at an increased rate when jolted with electricity between 50,000 and 100,000 volts for one ten-millionth of a second. The jolts more than doubled the yield of certain mushrooms in contrast to conventional farming methods.
“We have tried these experiments with ten types of mushroom so far and have found that it is effective in eight species,” said Koichi Takaki, an associate professor in engineering at Iwate University. “We saw the best effects in shiitake and nameko mushrooms, while we also tested reishi mushrooms, which are not edible but are used in certain types of traditional Chinese medicine,” he said.
The researchers theorize that the shocked mushrooms are reacting to danger by giving themselves a reproductive boost. “For mushrooms, a lightning strike would be a very serious threat that could easily kill them off,” said Yuichi Sakamoto, chief researcher at the Iwate Biotechnology Research Center, who has been working with Takaki’s team. “I think they have the need to regenerate before they die, and when they sense lightning, they automatically accelerate their development” and produce more fruiting bodies, he said.
Researchers are working on the development of lightening machines to deliver controlled electrical bursts to mushroom harvests. “We want to collaborate with commercial mushroom farmers and eventually commercialize this technology,” said Takaki.
This new harvesting method could significantly increase food production for the Japanese food industry where mushrooms are the centerpiece of many Japanese diets; Japan imports about 50,000 tons of mushrooms a year, mainly from China and South Korea.
This electrical jolt research couldn’t have come at a more opportune time since Japan’s agricultural ecosystem, known as satoyama, has been on the decline from land development. Satoyama — a border region between arable land and the mountains of the developed Japanese countryside — supplies an environment for thousands of native wildlife species, and supports villages and small farms.
But rural landowners have sold their farms to developers; and ancient satoyama landscape has been transformed into golf courses, factories, and housing. Additionally, mud-lined irrigation ditches were updated and re-lined with concrete to increase water flow, but the concrete ditches have negatively impacted wetland wildlife.
“There are some really quite dramatic changes in many areas as farmers abandon portions of the landscape, especially rice paddies that are small and inefficient,” said Kevin Short, a professor of environmental education at the Tokyo University of Information Sciences. “As farmers are becoming older, there are fewer young people coming to work the land,” Short said.
The Iwate University team is also testing other crops with electrical jolts — to date, radish, rapeseed, beans and some varieties of lily are showing increased growth rates when electric current is applied.