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It is no longer a new thing to cultivate leafy vegetables with artificial light and nutrient solution. Many Japanese companies use the waste factory to “plant vegetables”. A plant factory in Chiba Prefecture, near Tokyo, differs in that the boxes from which the seedlings are grown are transported to the plant factories in the underground space, and the vegetables that are finally grown are sent to the ground by conveyor belts to achieve full automation planting vegetables.

This is the world’s first underground fully automated plant factory, located in an idle underground municipal complex. The top of the underground tunnel of about 3.1 kilometers is about 5 meters from the ground, the interior is 6 meters to 8 meters wide, and the height is about 4 meters. It was first built in 1995. It was originally planned to be used in the local municipal integrated pipe network and was left unused. Ito Electric Co., Ltd., which develops automation equipment, cooperates with the Chiba Prefecture Corporate Land Administration to utilize this idle underground tunnel. In December 2017, this unique plant factory was built.

According to Okada Akira, head of the Plant Factory Development Headquarters of Ito Electric Co., Ltd., starting from December 2017, the plant factory began to test and cultivate 200 vegetables per day, including leafy vegetables such as lettuce and edible flowers. According to the plan, by 2020, the factory can enter the mass production period and produce 2,500 per day. By 2022, the daily output will be further expanded to 5,000. By then, the underground plant area will reach approximately 3,200 square meters, and the above-ground working area will reach approximately 600 square meters.

It is reported that part of the tunnel has been opened up as a fully enclosed plant growing area with an area of ​​about 120 square meters. Through the plastic wall curtain, some vegetables such as lettuce can be seen layered inside.

According to Okada Akira, the plant has been fully automated. After cultivating the seedlings on the ground, the modular vegetable box is sent underground through the conveyor belt. The LED grow light and nutrient solution transport in the underground plant can be completed automatically. The underground plant factory can be transported to the ground for sale after 24 days of cultivation.

The staff also brought freshly harvested lettuce to the reporter for tasting. Due to the complete cultivation in a non-polluting environment, these lettuces can be eaten directly without washing, and the taste is also very good.

Okada said that the vegetable sales price of the plant is now the same as that of ordinary lettuce, and there is room for further cost reduction in the future. When the daily output reaches 5,000, the ground only needs about 10 staff for seedling, harvesting and equipment maintenance. In the future, they plan to develop more automation equipment, with the goal of reducing costs by 20% to 30%.

According to Toshihiko, the deputy director of the Chiba County Enterprise Land Administration, plant factories usually need to consume a lot of electricity for temperature control and lighting, but this plant is set up in an underground tunnel, constant temperature and humidity throughout the year, which can save a lot of air-conditioning electricity costs. . In addition, due to the close proximity to the consumer market, the vegetables produced do not need to be transported over long distances, saving a lot of logistics costs.