Journal of Agricultural Meteorology
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
Volume 47, Issue 2
Displaying 1-8 of 8 articles from this issue
  • Takuya KOBAYASHI, Yoshihisa KOHNO, Keiichi NAKAYAMA
    1991 Volume 47 Issue 2 Pages 83-90
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    This report described changes in the growth processes and yield of soybean plants exposed to simulated acid rain at pH 5.6, 4.0, 3.0 and 2.0 containing sulfate, nitrate and chloride by using analysis of growth parameters and seed yield components.
    The analysis of growth parameters showed that LAR (leaf area ratio) and SLA (specific leaf area) for soybean plants at pH 2.0 from 1 week after the initiation of exposure were significantly smaller than those at pH 5.6. The application of simulated acid rain at pH 2.0 decreased RGR (relative growth rate) as compared with that at pH 5.6. Since RGR is expressed in the form of NAR (net assimiration rate)×LAR, lower RGR at pH 2.0 is associated with reduction of LAR due to small leaf area.
    The yield component analysis indicated that the significant reduction of seed dry weight per plant at pH 2.0 were attributed to significant decrease in number of seeds per pod. Such a reduction in seed number at pH 2.0 resulted from increasing number of empty seeds.
    pH of cultivated soil especially at the upper soil layer (0-5cm from surface) exposed to simulated acid rain for 9 weeks was decreased with increasing acidity of simulated acid rain. At the lower layer (25-30cm), however, there was no significant difference in soil pH among any treatments.
    These results suggested that the exposure of simulated acid rain at pH 2.0 caused the reduction of dry weight growth and seed yield of soybean plant due to acute damage of leaf area growth. However, at a pH above 3.0 there was no significant effect on the growth processes and yield components of soybean plant. Based on our results current pH level of ambient rain in japan should not have an adverse impact on the growth and seed yield of soybean.
    Download PDF (1036K)
  • Kazuo TOBE, Hiroo TAKAGI, Kenji OMASA
    1991 Volume 47 Issue 2 Pages 91-94
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Peroxyacetyl nitrate (PAN) concentration was automatically controlled in a PAN expoeure system for plant to enable accurate PAN exposure experiments to be carried out effectively.
    Gaseous PAN generated by bubbling nitrogen into a dilute PAN solution was introduced to air stream which blowed into an exposure box. The PAN concentration in the exposure box was measured with a chemiluminescent NOx analyzer continuosly and with an electron capture detection gas chromatograph (ECD-GC) at 7-min intervals. The PAN concentration was controlled with a computer as follows: (1) the flow rate of nitrogen introduced into the PAN solution was PID-controlled continuously to maintain a constant NOx analyzer response between ECD-GC outputs; (2) the NOx analyzer was recalibrated for PAN concentration at 7-min intervals by ECD-GC.
    Using this system, PAN concentration in exposure air was kept within a range of ±5% deviation from a desired set point in the major time course of an experiment.
    Download PDF (446K)
  • Yoshitaka KUROSE
    1991 Volume 47 Issue 2 Pages 95-99
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Using the elevation data, which was offered by the National Land Numerical Information with 250-m grid size, an estimation model was proposed for the evaluation of radiation conditions as a potential income of solar energy.
    The main subjects of the present study are verifications of the proposed model, and clarifications of the influence of solar radiation income on the theramal environment and on the location of agricultural land use.
    The results were summarized as follows:
    The estimation by the grid size of 250-m feasibly represents the solar radiation conditions over complex terrains. However, in case of complex terrains which is tangled with valley and ridge, there is not enough of estimation by the grid size of 250-m. The estimation by the grid size of 1-km tends to overestimate solar radiation on a slope compared with the estimation by the grid size of 250-m.
    There is a linear relation between the surface temperature and the solar radiation flux estimated with 250-m grid size over forest area.
    Especially in the typical mountainous regions, farms are located just around the area of the high-insolation-condition, which is defined by the model as the most comfortable environment.
    Download PDF (4840K)
  • Kazuhiro FUJIWARA
    1991 Volume 47 Issue 2 Pages 101-107
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (1099K)
  • Koji SHIGEHARA
    1991 Volume 47 Issue 2 Pages 109-116
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (1076K)
  • Yukio OZAWA
    1991 Volume 47 Issue 2 Pages 117-121
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (708K)
  • Working Group on Meteorological Improvement Studie
    1991 Volume 47 Issue 2 Pages 123-126
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (525K)
  • 1991 Volume 47 Issue 2 Pages 127-133
    Published: September 10, 1991
    Released on J-STAGE: February 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (1027K)
feedback
Top