1996 Fiscal Year Final Research Report Summary
OPTIMUM CONTROL OF IRRIGATION SYSTEM FOR HYDROCULTURE USING BIOMASS BED WITH TWO INPUTS OF TRANSPIRATION AND WATER CONTENTS
| Project/Area Number |
07456113
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
農業機械学
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| Research Institution | SHIMANE UNIVERSITY |
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Principal Investigator |
FUJIURA Tateshi Shimane University, Faculty of Life and Environmental Science, Professor, 生物資源科学部, 教授 (00026585)
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| Co-Investigator(Kenkyū-buntansha) |
IM Gyuwan Shimane University, Faculty of Life and Environmental Science, Lecturer, 生物資源科学部, 講師 (50252903)
TAKEYAMA Kouichi Shimane University, Faculty of Life and Environmental Science, Professor, 生物資源科学部, 教授 (20032625)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Bark of Japanese cedar and cypress / Bark bed / Irrigation control / Transpiration flow rate / Thermal conductivity |
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| Research Abstract |
This study was done to improve and popularize the hydro- cultivation with the compressed bed of Japanese cedar and cypress, and to develop an automatic, irrigation and heating systems for that. Therefore, physical properties, water holding performance, drying characteristic and heat couductivity of the bed were investigated.
(1) The essential oil that is contained in the bed interrupts the water absorption. The bed became absorbent of water by flooding in the water. The essential oil that is contained in the bed was considered effective to prevent the rot of the bed.
(2) The bed was moistened by flooding into the water. Time required to saturate it with water was 12 hours after flooding it.
(3) After moistening, the bed was put n a net to drain the excess water. After five minutes, the apparent volume distribution of solid, liquid and gas phases were 26,28 and 46% respectively. This large ratio of gas phase showed that the gas permeability was high.
(4) Cherry tomatoes were planted in the biomass bed, and its growth and the pF value of the bed were measured to investigate optimum control of the irrigation.
(5) The response time of the stalk diameter increased with the pF value. The transpiration flow rate decreased with the increasing pF value. It was suggested that the pF value in the irrigated bark bed should be less than 1.6-1.7 for the growth of cherry tomatoes.
(6) The thermal conductivity of the biomass bed was about 1/3 of that of the rock wool bed. The low thermal conductivity saves the heating energy of the bed.
Consequently, the bark materials of Japanese ceder and cypress were considered suitable for the hydro-cultivation bed.
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