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Volume 26 (1988)
- Issue 4 Pages 151-
- Issue 3 Pages 83-
- Issue 2 Pages 45-
- Issue 1 Pages 1-
Volume 26, Issue 4
Displaying 1-7 of 7 articles from this issue
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Souichi NISHIYAMA, Tosio CHO, Kazuo KOJIMA1988 Volume 26 Issue 4 Pages 151-155
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSIn the drip irrigation system, the variation in head along the lateral line changes emitter discharge along line. Because of this reason, usually, it is impossible to gain the same emitter discharge along the line. But in the drip irrigation system with microtubing, by the selection of length of microtubing in accordance with the head in lateral line, the same emitter discharge along the line is gained.
The friction factor in microtubing was examined experimentally. The result indicated that the friction factor is shown by 64/Re in laminar flow in which Re is Reynolds number. There are two flow pattern occurred at the tip of the microtubing. One is the drip flow and the other hand is the jet flow. The boundary of drip and jet flow in microtubing was clarified experimentally. If the jet flow is used, the soil errosion occurs, therefore we must keep the drip flow at the tip of microtubing.
The characteristics of the design method proposed in this paper are as follows.
1. The emitter discharge along the lateral line is same.
2. The drip flow occur at the tip of microtubing.
For the application in the field, the analysis example was shown.View full abstractDownload PDF (488K) -
Souichi NISHIYAMA, Tosio CHO, Kazuo KOJIMA1988 Volume 26 Issue 4 Pages 157-162
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSThe main purpose of the design for drip irrigation is uniform application of wat in the field. Usually, the designer examines uniformity of the emitter discharge along the lateral line. For this purpose, it is necessary to calculate the distribution of pressure along the lateral line. However, the calculation of these is generally complex. In this paper, therefore, a simple calculation method of the pressure distribution was proposed. The effects of error in friction factor and the emitter discharge on friction head loss were considered. The results indicated that emitter discharge should be estimated as accurately as possible. Therefore, to decrease the variance of emitter discharge in the whole lateral line, uniform discharge in several segments of the line was used for calculation.
The friction factors used were as follows:
Re<2000, f=64/Re; Re>2000, f=0.3164 Re, where Re and f are Reynolds number and friction factor, respectively. The putative calculation of pressure distribution proved to be as accurate as that in exactly analysis.View full abstractDownload PDF (530K) -
(2) Dynamics of Water Content in Plants such as Several Crops and Trees under Natural ConditionsKenzo IWAO, Taikichi TAKANO1988 Volume 26 Issue 4 Pages 163-170
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSThis paper reports the characteristics of daily variations of water content of several crops and trees, that is, plant water dynamics under natural conditions. They were obtained by the measurements as the application of our non-invasive and continuous measurements of water content in plant. Those methods were reported in previous report (No. 1) .
The main results obtained through the measurements were as follows.
(1) Daily variations of plant stem diameter as the index of water content under various weathers
(2) Relationship between stem diameter and water potential in plant tissue.
(3) Relationship between the daily variations of stem diameter and stomatal aperture of a plant.
(4) Transient responses of the water content in a plant to the watering.
(5) Plant stem shrinkage according to the drought of soil.
(6) Oscillation in stem diameter observed in its daily variation.View full abstractDownload PDF (919K) -
Youlin YI, Yasushi HASHIMOTO1988 Volume 26 Issue 4 Pages 171-174
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSPhotosynthesis of plants is an important physiological process for the growing of plants cultivated in the plant factory. Photosynthesis is affected by light intensity and CO2 concentration and the relationship between them is nonlinear. But at present, it was identified with a linear system model by limiting them in the linear area. For an optimal photosynthesis by controlling the light intensity and CO2 concentration in the plant factory, it is necessary to identify the photosynthesis response to the light intensity and CO2 concentration in wide range.
In this study, we used GMDH (Group Method of Data Handling) to identify the photosynthesis of Okayama saradana affected by CO2 concentration and light intensity as a nonlinear system. At first, we took the light intensity as the input and identified the photosynthesis with linear and nonlinear models. The linear model resulted in a great error comparing that estimated with the nonlinear model. Furthermore, we took both the light intensity and the CO2 concentration as the inputs and applied GMDH to the identification. Results showed that the nonlinear characteristics of photosynthesis affected by the two environmental factors can be satisfactorily identified with GMDH method.View full abstractDownload PDF (458K) -
Naoshi KONDO1988 Volume 26 Issue 4 Pages 175-183
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSIn this study, spectral reflectances of parts of fruit vegetables were measured and degree of discrimination between them in some pairs of wavelength bands was calculated in order to distinguish each part of fruit vegetables from others. The results were given as follows:
1. Spectral reflectances of all leaves which were measured in this time were almost similar, but those of different color fruits were different in the visible region and those of all fruits could be classified into higher type and lower type than their leaves in the near-infrared region. Reflectances of flowers were different in the visible region, and those were similar in the nearinfrared region. Water absorption bands were observed at 970 nm and 1170 nm wavelength only in fruits and stems, and were observed at 1450 nm and 1950 nm in all parts.
2. 670 nm wavelength was effective for discrimination of fruit whose color was red or yellow such as a tomato, 800-900 nm was for fruit whose reflectance was higher than the other parts in the near-infrared region such as a eggplant or a cucumber, 1950 nm was for a eggplant stem, and 1450 nm was for a sweet pepper fruit. It was considered that the discrimination became easier when these wavelengths were combined with another characteristic wavelength.View full abstractDownload PDF (763K) -
Kenji HATO, Hiroshige NISHINA, Sojiro CHIKAIZUMI, Yasushi HASHIMOTO1988 Volume 26 Issue 4 Pages 185-186
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSAs the first step of application of AI (Artificial Intelligence) to agriculture, an expert system was constructed. This system makes diagnoses of disease and insect damage of satsuma mandarin and also suggests control methods for better growth. The system was constructed on ‘NEC PC-9801’ personal computer, using ‘Sogen’ which is a Japanese expert shell. Knowledge on disease and insect damage was rearranged and expressed in production rules, composing knowledge base.
The expert system works well and makes correct diagnoses. In the future, such applications of AI would be more important in agriculture.View full abstractDownload PDF (214K) -
Volume 26 (1988)1988 Volume 26 Issue 4 Pages 189-192
Published: December 31, 1988
Released on J-STAGE: June 22, 2010
JOURNAL FREE ACCESSDownload PDF (315K)
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