Atsumasa Yoshida1, Hironori Oka1, Shinichi Kinoshita This email address is being protected from spambots. You need JavaScript enabled to view it.1, Ayumi Enjoji2, and Junichi Yamaguchi2

1Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-Ku, Sakai, Osaka 599-8531, Japan
2Osaka Sakai Plant Factory Corporation, 1-1 Gakuen-cho, Naka-Ku, Sakai, Osaka 599-8531, Japan


Received: January 22, 2021
Accepted: October 3, 2021
Publication Date: December 23, 2021

 Copyright The Author(s). This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are cited.

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It is necessary to optimize and homogenize the environmental conditions in plant factories. We installed sensors to observe the environmental factors in a plant factory and evaluated lettuce growth. We found that the integrated quantity of PPFD (Photosynthetic Photon Flux Density) is correlated with fresh weight of harvested leaf lettuces and that lettuce density also affects growth. There is the relationship between adjacent and central plant stocks. The influence of planting density was observed, and thinning improved the growing conditions at many planting positions. On the other hand, it was concluded that the air temperature and humidity were uniform in the plant cultivation bed and did not affect the growing condition. It was observed that the air temperature, humidity and wind speed were affected when the cultivation bed was in front of the air conditioning port. The CO2 concentration was controlled within a range that did not affect the growth.

Keywords: Large-scale plant factory, growth diagnosis, environmental conditions, light intensity, cultivation density


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