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Volume 49, Issue 1
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Toshikazu KAWAKATA, Masaharu YAJIMA1993 Volume 49 Issue 1 Pages 3-9
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSMany studies concerning photoperiodic sensitivity of rice plants have been conducted under constant daylength. However, since daylength fluctuates periodically during the year, we examined photoperiodically sensitive rice under natural daylength (and constant air temperature) to predict heading time using meteorological data.
Six cultivars of rice plants were sown at two-week intervals for one year in a green house. Air temperature was maintained at a constant 24 degrees C during the year, but water temperature decreased during winter.
Cultivars sown between August and February were nearly constant in number of days required from emergence to heading. However, cultivars sown between March and July required more time, and results among cultivars were in consistent.
From these results, the authors propose the following equation:
Σhi=1Ti-S=Σhi=a+1f(Li)
where Ti is water temperature, Li is daylength on the i-th day, S is accumulated water temperature from emergence to heading under short daylength, a is the date on which rice plants start to sence daylength and h is heading date, f(L) was calculated by non-parametric DVR methods.
In conclusion, this model can be transformed into the developmental index (DVI) which is the sum of the developmental rates (DVR). And the developmental rate was constant when daylength was shorter than critical one. Over this critical value, however, the developmental rate decreased in direct proportion to daylength.View full abstractDownload PDF (804K) -
Yoshitaka KUROSE, Yousay HAYASHI1993 Volume 49 Issue 1 Pages 11-17
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSUsing the thermal images offered by the infra-red thermometer and the LANDSAT, the air temperature distribution over mountainous regions were estimated under conditions of nocturnal radiative cooling in the winter season. The thermal image analyses by using an infra-red thermometer and the micrometeological observation were carried out around Zentsuji Kagawa prefecture. At the same time, the thermal image analyses were carried out by using the LANDSAT data. The LANDSAT data were taken on Dec. 7, 1984 and Dec. 5, 1989. The scenes covered the west part of Shikoku, southwest of Japan.
The results were summarized as follows:
Values of the surface temperature of trees, which were measured by an infra-red thermometer, were almost equal to the air temperature. On the other hand, DN values detected by LANDSAT over forest area were closely related with air temperature observed by AMeDAS. Therfore, it is possible to evaluate instantaneously a spatial distribution of the nocturnal air temperature from thermal image.
The LANDSAT detect a surface temperature over Shikoku area only at 21:30. When radiative cooling was dominant, the thermal belt and the cold air lake were already formed on the mountain slopes at 21:30. Therfore, it is possible to estimate the characteristic of nocturnal temperature distribution by using LANDSAT data.
It became clear that the temperature distribution estimated by thermal images offered by the infra-red thermometer and the LANDSAT was useful for the evaluation of rational land use for winter crops.View full abstractDownload PDF (2811K) -
Osamu TSUKAMOTO1993 Volume 49 Issue 1 Pages 19-25
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSTurbulent flux measurements were carried out over a paddy field to study the irrigation water effect. The ponding depth ranged from 0cm to 10cm with fine weather during a week. Upward sensible heat flux responded to the variation of water level with a maximum on no water condition. Downward carbon dioxide flux had a minimum value on no water condition. However, water vapor flux behavior is more complicated with a minimum on full water condition.
The influences on the Bowen ratio and CWFR (Carbon dioxide Water Flux Ratio) were also studied.View full abstractDownload PDF (2179K) -
Haruo SUZUKI, Hajime OHRO1993 Volume 49 Issue 1 Pages 27-34
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSHorizontal distributions of soil temperatures beneath the mulch film in a soybean field were studied in relation to the meteorological conditions. Mulching material was black polyethylene film (0.04mm thick) with planting holes (8cm dia.). The experimental plots were designed as follows:
Co plot was not planted and not mulched, Cp plot was planted and not mulched, Mn plot was not planted and mulched, and Mp plot was planted and mulched.
1) Daily variations in the standard deviations of 10 soil temperatures at 10cm depth in each plot were in the following order: At night, Mp>Mn>Cp≈Co. Canopy covering plot Mp caused deviations in the 10 soil temperatures to increase to a great extent. In the daytime, the deviations in all the plots increased, and differences in the deviations among the 4 plots decreased more than at night.
2) Soil temperature relations between two plots, three cases in total, have been classified into two groups: the most frequent and the rest, so as to analyze them all using the discriminant function of the meteorological factors as explanatory variables. An analysis of those between mulched plot Mp and bare plot Co showed that the soil moisture and LAI affected the classification of both plots into the two groups to a considerable extent.
3) A comparison of the soil temperature between the two plots was made by arbitrarily fixing the threshold which was the soil temperature difference. The soil temperature difference between the two plots varied according to the value of the thresholds. When either of the plots had a canopy, comparing both of them involved fixing the threshold according to plant growth.View full abstractDownload PDF (1130K) -
Atsushi KANO, Nanami NAGATANI1993 Volume 49 Issue 1 Pages 35-39
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSWe have developed two CAI (Computer Aided Instruction) application software for the use of students at agricultural colleges. Hardware and software platforms for the applications are Macintosh SE (Apple Computer) and HyperCard ver. 1.2.1 (Apple Computer). The developed software (stacks) use graphical images, sounds, and animation techniques to keep users attracted to the screen. They also contain pop-up explanations of words and terms and mini-tests for understanding technical words and for self understanding user's achievement on the subjects, respectively.
According to results of questionnaires answered by the test users, in general, the stacks were judged as easy to use and user friendly. However, the users indicated some points need to be improved. Future improvement on the user interface is necessary; at the same time, it is also necessary to keep the developmental environment simple for non-professional programmers.View full abstractDownload PDF (477K) -
Osamu KITAMURA1993 Volume 49 Issue 1 Pages 41-47
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
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Secretariat of DCVF Symposium1993 Volume 49 Issue 1 Pages 49-52
Published: June 10, 1993
Released on J-STAGE: February 25, 2010
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1993 Volume 49 Issue 1 Pages 80a
Published: 1993
Released on J-STAGE: February 25, 2010
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1993 Volume 49 Issue 1 Pages 80b
Published: 1993
Released on J-STAGE: February 25, 2010
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1993 Volume 49 Issue 1 Pages 80c
Published: 1993
Released on J-STAGE: February 25, 2010
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