Journal of the Society of Agricultural Structures, Japan
Online ISSN : 2186-0122
Print ISSN : 0388-8517
ISSN-L : 0388-8517
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Volume 41, Issue 4
Vol. 41, No. 4 (Ser. No. 128)
Displaying 1-3 of 3 articles from this issue
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  • Studies on Growth Control Using Water Stress and LED Lighting for the Normal Temperature Preservation of Tomato Seedlings
    Shingo MIYAMOTO, Takuma GENKAWA, Toshitaka UCHINO
    2011 Volume 41 Issue 4 Pages 156-162
    Published: 2011
    Released on J-STAGE: July 07, 2023
    DOIhttps://doi.org/10.11449/sasj.41.4_156
    JOURNAL OPEN ACCESS
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    The effect of light quality and intensity on normal temperature preservation of tomato seedlings under water stress conditions was evaluated. Under severe water stress conditions, the growth rate of tomato seedlings was greatly inhibited, thereby resulting in poor development of the fi rst fl ower buds. The growth of plant height and stem diameter was delayed when the PPFD (photosynthetic photon fl ux density) was less than 20μmolm-2s-1, but increased when the light intensity was above 20μmolm-2s-1. The tomato seedlinga were grown under a PPFD of 20μmolm-2s-1 with LEDs of red to blue light (LED2:1, LED1:1, LED1:2) and gradually decreasing supply of culture fl uid keeping the plants without wilting. As a result, the growth of tomato seedlings was well inhibited under LED1:2. The LED ratio of ”Red: blue =1:2” and asymptotic process of water stress conditions were effective for the growth control of the tomato seedlings and the tomato seedlings were able to be stored for 3-4 weeks at normal temperature.
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  • Development of the Equipment for Measuring the Overall Heat Transfer Coeffi cient of Greenhouse Covering Materials
    Makio HAYASHI, Motohiro OOHARA, Michiko SHIMIZU, Takayoshi YAMAMOTO
    2011 Volume 41 Issue 4 Pages 163-169
    Published: 2011
    Released on J-STAGE: July 07, 2023
    DOIhttps://doi.org/10.11449/sasj.41.4_163
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    The equipment for measuring the overall heat transfer coeffi cient of greenhouse covering materials was developed, and its performance was tested in a trial operation. The main unit consists of a heating chamber representing the greenhouse (bottom half) and a cooling chamber representing the exterior of the greenhouse (top half). One to three layers of the covering material to be analyzed can be installed to form a partition between these two chambers. It is known that the amount of heat transferred through greenhouse covering materials is affected by both the amount of atmospheric longwave (infrared) radiation and the external wind speed. In the developed equipment, atmospheric longwave radiation under clear or cloudy conditions can be simulated by controlling the temperature of a cooling panel installed on the ceiling of the cooling chamber, and different wind speeds can be simulated by adjusting small fans installed in the cooling chamber. Changes in temperature over time from the start of operation for each part of the equipment, temperature and wind-speed distributions within the cooling chamber, and the heat budget of the heating chamber were measured to test the equipment. During this trial operation, characteristics of the equipment were clarifi ed. The overall heat transfer coeffi cient of plastic fi lm (polyethylene) was measured using different cooling panel temperatures, and the k values obtained were nearly equal to the conventional values used for calculating the heating loads of greenhouses, demonstrating the validity of the equipment.
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  • Integration of Centralized Biogas Plant and Its Performance in Cold Region
    KIKUCHI Sadao, Kazutaka UMETSU, Masahiro IWASAKI, Yoshiaki TAKEUCHI, M ...
    2011 Volume 41 Issue 4 Pages 170-178
    Published: 2011
    Released on J-STAGE: July 07, 2023
    DOIhttps://doi.org/10.11449/sasj.41.4_170
    JOURNAL OPEN ACCESS
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    Centralized biogas plant for dairy manure from 1 300 cattle heads was built in Shikaoi town in Hokkaido with the capacity of manure loading of 85.8t/day, with 37 days of average HRT and operated at 38℃ temperature. In fi scal year 2008, utilization rate was 71% as the manure loading rate was 61.3t/day for the planned processing amount of 85.8t/ day. Therefore, the average HRT was increased to 52.2 days. From the average biogas production of 2 338m3/day, 92% was consumed in power generation. Average methane concentration of produced biogas was 57.6% and H2S concentration was decreased up to about 40ppm. The average amount of power generation was 3 742 kilowatt-hour/day and 54% of the power was used in the facility itself while 46% was sold to Hokkaido electric power company. The applied area of digested slurry in fi scal year 2008 was 561ha and the amount of applied slurry was 18 440t.
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