Journal of Agricultural Meteorology
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
Volume 55, Issue 2
Displaying 1-12 of 12 articles from this issue
  • Yasushi ABE, Kyoichi OTSUKI, Makio KAMICHIKA
    1999 Volume 55 Issue 2 Pages 101-108
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    The authors have developed a “Earth-Air Heat Exchange Distillation System” for collecting water from vapor originated in evapotranspiration. This system distills water from vapor by cooling the air in a greenhouse, using underground heat exchange pipes. It is similar to “Soil Heat Exchanger-Storage Systems”. A parameter for estimating the daily amount of collected water was investigated, based on heat and vapor budget of the heat exchange pipe. The results indicate that the daily amount of collected water is a linear function of the integrated surplus of air-soil temperature.
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  • Ken HAMOTANI, Nobutaka MONJI
    1999 Volume 55 Issue 2 Pages 109-115
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    A low power (0.1W) and light weight (probe weight 270g and circuit weight 80g) one-dimensional sonic anemometer-thermometer was developed. The measuring span of the anemometer is 10cm, sound frequency is 40kHz and alternation frequency of the sound direction is 78Hz. The low power consumption was attained by using ceramic transducers, which can be driven by low voltage pulses (5V peak-to-peak) and by adapting CMOS logic to the circuit.
    A field test was carried out in a coniferous forest with a commercial sonic anemometer and a fine thermocouple thermometer. Comparison of the output signal and spectra from each sonic anemometer indicated good agreement.
    The characteristics of the sonic anemometer-thermometer are low power consumption and light weight. These features are useful for measurements from a small tethered balloon or at places where the electrical power is limited.
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  • Yousay HAYASHI, Hitoshi TORITANI, Shinkichi GOTO, Hiromitsu KANNO, Yeo ...
    1999 Volume 55 Issue 2 Pages 117-125
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Agricultural activities and crop production will be affected if and when climate deviates from the normal. In the eastern part of Asia, i.e. the region including Japan and Korea, effects of climate variations on the yield of paddy rice were demonstrated dramatically by a climatic regime known as a Blocking High. In 1993 the Tohoku district of Japan and Korea were affected by a severely low temperature anomaly ranging from -2.8°C to -3.7°C in monthly averages. This caused reductions of rice yield of -45% and -9% in the Tohoku district and Korea respectively. The spatial distribution of the yield anomaly indicated that a cold current derived from the Okhotsk High simultaneously attacked the east part of both countries. This event showed that a similar depression in rice production should appear in both countries when cool summers occur. Fortunately, these negative anomalies were balanced by high production in the hot summer of 1994.
    To project the influence of the temperature anomaly on the production of paddy rice, correlation analyses were carried out. A curve, ΔY=-0.89×exp (-0.34×ΔT)+1, was obtained with r=0.698. Here, ΔY is the anomaly of rice yield, ΔT is that of averaged temperature through July to September. Using this relationship, changes of rice production were projected against temperature anomaly and ranged from +13% with ΔT=+3°C to -39% with ΔT=-3°C.
    Variations of paddy rice production, over the regions of Tohoku district and Kore, coincided with a penetration of cold-NE-current into their eastern zones along the coast. This event will trigger a food problem in East Asia under possible fluctuations of summer temperature. In addition, arable lands have been devastated and population will grow up to 1.5 times the present population by the middle of the next century. Evaluation of the vulnerability of agriculture in East Asia, where paddy rice is a main crop, will be an important subject for scientists and for policy makers.
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  • Kimio INOUE, Kou NAKAZONO, Hiromitsu KANNO
    1999 Volume 55 Issue 2 Pages 127-135
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    As reported by many agronomists, the direct seeding cultivation of rice is thought to be an effective way to reduce the cost of rice production in Japan. However, the rice yield of direct seeding cultivation is generally lower and unstable compared with that from transplanting cultivation. This is mainly due to the unstable establishment of rice seedlings and slow growth during the early growing stage. The two reasons mentioned above are correlated with an appropriate control of water depth under changing weather conditions.
    This report describes an automatic irrigation system based on the rice microclimate prediction model (Inoue, 1985). This irrigation system can appropriately control water depth and accordingly the microclimate of direct seeding rice fields using weather data and rice plant data. The feasibility tests of this system were done at two direct seeding rice fields at Yuza-machi, Yamagata Prefecture in 1995 and at Yawara-mura, Ibaraki Prefecture in 1997, respectively.
    The results obtained from the above two experiments can be summarized as follows:
    The newly developed automatic irrigation system showed good performance in controlling the water depth of direct seeding rice fields during the whole rice growing season. The brown rice yield from the field controlled by this system was 562kg/10a, while neighboring direct seeding rice fields, in which the water depth was controlled manuall, had yields of 492kg/10a and 505kg/10a in 1997. The plant height of the test field with the automatic irrigation system was about 75cm, compared to about 70cm in neighboring direct seeding cultures.
    These results show that the newly developed automatic irrigation system was effective in stabilizing the establishment and emergence of rice seedlings, and in promoting subsequent growth in direct seeding cultures.
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  • Nanping SANG, Tetsuo KOBAYASHI
    1999 Volume 55 Issue 2 Pages 137-143
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    The radiative flux in the lowest three meters above a bare-soil surface was directly measured on calm nights with little cloud cover. Although divergence of upward radiative flux occurred above 1m, convergence was often observed between 0.2m and 1m all through the night. Almost the same results were obtained for the net flux except that the transitional height between divergence and convergence was some tens of centimeters, which means that radiative warming occurred just above the bare-soil surface during the night. This phenomenon can be explained by postulating that cold air is produced by conduction at the surface of small heat-insulated projections (HIPs) such as soil grains on the ground surface, while the ground releases the heat stored during the day by radiation through the pores between HIPs and warms the air immediately above the surface at night. This “HIP hypothesis” can also account for the so-called “raised minimum (RM)” phenomenon.
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  • Tomoaki KOMORI, Ryoko IKEMOTO
    1999 Volume 55 Issue 2 Pages 145-153
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Analytical solutions for the CO2 concentration profile CA (z, t) and CO2 mass transfer coefficient kL within the assimilation cell phase of the crop leaf in the net photosynthesis process were obtained by the concept of “rate of process” in the engineering science.
    To solve the CO2 mass transfer problem of the crop leaf in net photosynthesis, CO2-H2O equilibrium at the assimilation-aerenchyma tissue interface within the crop leaf, Henry's Law, was introduced and the net photosynthetic reaction was approximated by a pseudo-1st order irreversible form.
    Simultaneously, in order to estimate quantitatively kL and the over-all gas phase CO2 mass transfer coefficient kG from the practical observed results of the net photosynthetic rate RA, the graphical method and its procedure were proposed, using the results of RA for “rice” presented by Yabuki (1992). The summary is as follows:
    1) CO2 mass transfer of a crop leaf in the photosynthesis process is a gas absorption-reaction. It is also a diffusion phenomenon in a gas-liquid binary system and the mechanism of CO2 absorption may be represented schematically by a “two-film penetration diffusion model”.
    2) Analytical solutions and the graphical method are available for evaluation of kL and kG from RA observed in the field. These basic analytical procedures for gas absorption engineering are useful to obtain the correlation of the net photosynthesis reaction rate constant k1 with RA and CO2 mass transfer coefficients.
    3) k1 is a primary characteristic parameter to evaluate the net photosynthetic ability of the crop. The over-all assimilation cell phase CO2 mass transfer coefficients, KL, kL, and kG depend on k1. Therefore, to estimate a valid RA or an appropriate net photosynthetic ability of the crop leaf, CO2 mass transfer coefficients correlated with k1 must be used.
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  • Kazuo TOBE, Kenji OMASA
    1999 Volume 55 Issue 2 Pages 155-163
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    To investigate leaf age dependence in the responses of photosynthetic functions to water stress, the changes in fluorescence parameters of bean (Phaseolus vulgaris L.) leaves were examined while the leaf water potential (ΨLW) was gradually decreased by withholding water supply to the soil; leaves of three different ages were used from each plant. No significant leaf age dependence was detected in any fluorescence parameters when the ΨLW was higher than -0.9MPa, the point at which the net CO2 uptake rate approached zero. However, at ΨLW lower than -0.9MPa, both the maximum PS II photochemical efficiency (FV/FM) and the quantum yield of non-cyclic electron transport in PS II (φe) decreased with decreasing ΨLW. The decreases in both FV/FM and φe were larger in younger leaves. More conspicuous leaf age dependence was detected in the response of the steady-state nonphotochemical quenching coefficient (qN). Water stress-induced changes in all these fluorescence parameters recovered to pre-stress levels within a day after rewatering. The results showed that the changes in the fluorescence parameters did not result from damage to the photosynthetic systems, but from changes in physiological conditions caused by the cessation of CO2 supply to the stroma or changes in stromal water status. It was concluded that leaf age is an important factor in determining the responses of fluorescence parameters to water stress.
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  • Hiroshi HAMAMOTO
    1999 Volume 55 Issue 2 Pages 165-172
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Response of vegetable seeds to irradiation and emergence of plants seeded at various depths were investigated to clarify the effects of solar radiation through soil on vegetable seed germination. Seeds of eight vegetable species were germinated in Petri dishes under 11-h irradiation per day. Seed germination was delayed in tomato (Licopersicon esculentum Mill.) but accelerated in perilla (Perilla ocymoides L.) and Japanese hornwort (Cryptotaenia japonica Hassk.) with increase in irradiation at the intensities higher than 0.4W m-2. Seeds of Japanese radish (Raphanus sativus L.), watermelon (Citrullus lanatus Matsum.), and Chinese cabbage (Brassica campestris L.) showed delayed germination at more than 4-6W m-2. No effect of irradiation on lettuce (Lactuca sativa L.) and carrot (Daucus carota L.) seed germination was seen. For tomato, Japanese radish and Japanese hornwort, the effects of irradiation time on germination were also investigated. Tomato seed germination was delayed and Japanese hornwort seed germination was accelerated with increase in irradiation time beyond 2h per day.
    The emergence of tomato and Japanese hornwort covered with Shimokuriyagawa loam soil (Kuriyagawa soil) and vermiculite at depths of less than 5mm, 5-10mm and 10-15mm was observed. Plants emerged more rapidly from 5-10mm depths than from less than 5mm depth in tomato. The plants seeded at 10-15mm depths emerged as rapidly as those at 5-10mm depths using vermiculite but later than those at other depths using Kuriyagawa soil, probably due to high bulk density. The early emergence of Japanese hornwort was fastest from less than 5mm depth. The plants seeded at 5-10mm depths did not emerge much slower than those at less than 5mm depth. A seeding depth of 5-10mm was suitable for the rapid emergence of those vegetables covered with both the soil and vermiculite.
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  • Yoshinobu HARAZONO, Masashi KOMINE, Kentaro TAKAGI, Hirokazu KOMURO
    1999 Volume 55 Issue 2 Pages 173-178
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    The “Ecosystem Database” has been developed to provide data on the issue of gas and energy exchange in various terrestrial ecosystems. These data are essential to verify modeling studies in global change issues but have not been available before. The data were obtained over grasslands, tundra, wetlands, shrub lands, dune, rice paddies and some agricultural fields. Numerical data were checked and quality controlled and then averaged for every 30min. In addition, the database includes site maps, photographs, and comments on data acquisition and quality. The Ecosystem Database is available through the World Wide Web. This system is designed to produce a requested graph, which allows users to select data that they want. The system will be open to the public beginning in October 1999. However the operation and control test will be provided for some researchers in advance.
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  • Toru UEDA
    1999 Volume 55 Issue 2 Pages 179-185
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
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  • Kazuyoshi KIMURA, Shigemi TANAKAMARU
    1999 Volume 55 Issue 2 Pages 187-191
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
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  • Recent Advances in Measurement of Evaporation and Loss of Intercepted Precipitation by Vegetation
    Working Group of Meteorological Improvement Studie
    1999 Volume 55 Issue 2 Pages 193-195
    Published: June 10, 1999
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
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