P33
宇宙農業における栽培培地の検討
Assessment of growing media for space agriculture
星野早紀 1, 佐藤直人 1, 丸尾裕一 2, 人見晋貴 2, 名倉理紗 3, 登尾浩助 1
Saki HOSHINO1, Naoto SATO2, Yuichi MARUO3, Shinki HITOMI4, Risa NAGURA5, Kosuke
NOBORIO6
明治大学農学部, School of Agriculture, Meiji University
明治大学大学院農学研究科, Graduate School of Agriculture, Meiji University
3 株式会社 Digital Blast, Digital Blast,Inc.
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1. Introduction

In recent years, research and development on space have been increasing for migration to other planets,
use of space resources and exploration of undeveloped land. Humanity’s exploration of Mars and theMoon is undertaken by international collaboration1). Although space agriculture is essential tohumanity’s exploration of Mars and the Moon, there are many restrictions on growing media, unlike
agriculture on Earth. For example, growing media should be virus free for safety2)3), since water
movement in loose materials is complicated due to the lack of a dominant gravity vector4), using porous
media with rigid pore spaces is desirable for reliable water management5). Furthermore, it is challenging
to use soil-like media for space agriculture. Therefore, choosing an inorganic growing media instead ofsoil to control water in space easily is necessary. This study, assessed growing media suitable for space
agriculture in closed environments such as the International Space Station and space bases.
2. Experiments

Plants grown in five different growing media (Excelsoil, Capillary mat, Cellulose sponge, Rockwool
block, and Granular rockwool) were compared withthose in Joint soil (Fig.1). Those growing media were
packed in nursery trays (300×600×15mm). Two seedsof cos lettuce (Lactuca sativa var. longifolia) were
sowed every 2.5 cm apart in a concentric pattern
after saturating the growing media with tap water(Fig.2). Water was applied with a drip emitter every
hour. The lettuce was grown for a month.
Germination and cotyledon opening rates were
measured weekly to evaluate the growth conditions.
Fig.1.

Six growing media used for the experiments.
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Fig.2. Location of seeds on a growing medium

3. Results and Discussions

Figure 3 shows germination and cotyledon opening rates on six growing media. Lettuce on Cellulose
sponge and Granular rockwool had almost the same germination rate as Joint soil. In addition, thecotyledon opening rate of Granular rockwool was higher than on Joint soil. However, germination andcotyledon opening rates on other three growing media (Excel soil, Capillary mat, Rockwool block) were
smaller than those on Joint soil. We concluded that Granular rockwool is the most suitable for growing
lettuce among the five growing media.

Fig.3. Germination and cotyledon opening rates on six growing media.
2 of 34. References

1) 宇宙航空研究開発機構 国際宇宙探査センター: 国際宇宙探査を巡る国際動向 (2018)https://www8.cao.go.jp/space/comittee/27-kiban/kiban-dai41/pdf/siryou3-1.pdf
2) Lunar Farming Concept Study Working Group: Report of Lunar Farming Concept Study Working
Group 1st, JAXA Special Publication, JAXA-SP-19-001 (2019)3) 科学技術・学術審議会 研究計画・評価分科会 宇宙開発利用部会: 国際宇宙ステーション(ISS)に提供する ISS 構成要素及び搭載物の安全性確認について(CALET 調査審議結果) (2015)
https://www.mext.go.jp/component/b_menu/shingi/toushin/__icsFiles/afieldfile/2015/08/03/1360235_1.pdf
4) John Graf, Barry Finger, Katherine Daues: Life Support Systems for the Space Environment, BasicTenets fir Designers Rev. A (2002)
5) Scott B. Jones, Robert Heinse, Gail E. Bingham, Dani Or: Modeling and Design of Optimal Growth
Media from Plant-Based Gas and Liquid Fluxes, SAE International (2005)© 2022 by the authors. Submitted for possible open access publication under theterms and conditions of the Creative Commons Attribution (CC BY) license(http://creativecommons.org/li censes/by/4.0/).

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