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Volume 50, Issue 2
Displaying 1-10 of 10 articles from this issue
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Guangling MAO, Kenji KURATA1994 Volume 50 Issue 2 Pages 97-100
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSEffect of rowcovers made of non-woven fabrics on wind profiles above vegetation model was studied in a wind tunnel. Three kinds of covering materials were placed directly on the wooden cylinder vegetation model. Two wind profiles of 0.46ms-1 and 0.92ms-1 at the height 45cm were created and parameters related to turbulent diffusion of momentum were calculated. Above the cover made of split fibers, turbulent diffusion was promoted, while that was suppressed above two kinds of spunbonded fibers compared to the case in which canopy was not covered. However, the change of the turbulent diffusion resistance by the covers was restricted to the range of 75-175%.View full abstractDownload PDF (483K) -
Junsei KONDO, Hiroaki OOKA1994 Volume 50 Issue 2 Pages 101-107
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSObservations of evaporation from bare soils (sand and loam) were carried out for a long term by using lysimeters. The decrease in evaporation from sand is larger than that from loam in drying processes after rainfall. The multilayer soil model (Kondo, 1993; 1994b; Kondo and Saigusa, 1994) simulates well the present observation of evaporation. Total amount of observed evaporation for a period of 416 days is 583mm, and that of calculated evaporation is 616mm. In the model the surface heat budget and diffusion of water vapor in the soil pores are taken into consideration.View full abstractDownload PDF (807K) -
Kazuyoshi KIMURA, Michiyo ARIYOSHI1994 Volume 50 Issue 2 Pages 109-113
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe effect of rainfall exposure on fresh weight, dry weight, and sugar and nitrogen contents of kidney bean plants (Phaseolus vulgaris L.) was investigated. Plants exposed to artificial rainfall treatment (mist of deionized water, 5mm/h) in a growth chamber (20°C, 61W/m2) for 5 days were compared to plants grown under the same conditions but without rainfall.
Rainfall (mist) treatment decreased the dry weight and the soluble sugar, starch and nitrogen contents of the plants. At the conclusion, the dry weight of the misted plants was 78% of that of the non-misted plants. The misted plants had 72% as much soluble sugar, 57% as much starch and 83% as much nitrogen as the non-misted plants. The differences between the misted and non-misted plants were larger in the shoots (leaf, stem) than those in the roots.
Dry weight and soluble sugar contents of the leaf and stem increased during 5 days of rainfall treatment, but the increases were smaller than those of the non-misted plants. Remarkably, starch content of the stems actually decreased during the 5-day rainfall treatment.View full abstractDownload PDF (597K) -
Toshikazu KAWAKATA, Masaharu YAJIMA1994 Volume 50 Issue 2 Pages 115-120
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThis study was conducted to develop a simple model of leaf dry weight and top dry weight of rice (Oryza sativa L.) plants. Rice variety “Nipponbare” was sown five times at one-month interval from April through August, 1992, and was transplanted in a paddy field at National Institute of Agro-Environmental Sciences (NIAES), Tsukuba, Japan about three weeks after the sowing. Plants samples were taken every two weeks to measure biomass and leaf area. Photon flux densities upon and below the rice canopies were measured to calculate light interception by the rice plants. Incident shortwave radiation and air temperature were recorded at the NIAES weather monitoring station. The data on biomass, light interception and the weather variables were used to develop the model. In the model, total leaf dry weight was described by a combination of exponential and linear functions of accumulated air temperature, and the dead leaf dry weight was expressed as a linear function of accumulated air temperature. Leaf dry weight was defined as the difference between the total and dead leaf dry weight, and was used to calculate light interception. Top dry weight was estimated as the product of the intercepted shortwave radiation and the radiation-use-efficiency (RUE). The model fitted rather well to the observation of the leaf dry weight, but it overestimated top dry weight with a constant RUE throughout the growing season. To correct the overestimation, the total leaf dry weight was further divided into active leaf dry weight and the senescent leaf dry weight, among which only the active leaf dry weight was used to calculate the light interception. The leaf senescence was assumed to be a function of accumulated air temperature. The revised model gave a good fit with regard to the top dry weight, and may be useful to represent crop production.View full abstractDownload PDF (834K) -
Effects of Simulated Acid Rain on Growth, Yield and Net-photosynthesis of Several Agricultural CropsTatsuo HOSONO, Isamu NOUCHI1994 Volume 50 Issue 2 Pages 121-127
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSEight species of crop were exposed to simulated acid rain (SO42-: NO3-: Cl-=2:1:2, equivalent ratio) at pH 5.6 (control), 3.0, 2.7 and 2.5 throughout their entire growing periods. Plant were subjected to acid rain treatment three times a week, for one hour with 7-13mm of precipitation at a time. Simulated acid rain at pH 3.0 or below produced foliar visible injury on leaves of all the tested plants in this study. Injury degree of the foliar visible symptoms was varied among plant species. In addition, injury degrees were different among leaf positions: injury was severer in lower lesf position, particularly cotyledons and primary leaves, than upper one. In many cases in this study, foliar visible injury was severer at the early stages of growth than the later stages. Dry weight of rice plants exposed to simulated acid rain at pH below 3.0 was reduced compared with pH 5.6 at early stage of growth. At the middle to late growth stage, however, acid rain treatment did not affect the growth of rice plants. The relationship between pH of simulated acid rain and yield loss in each crop suggested that acid rain at pH 3.0 or less acidity would not cause yield reduction at any crop. In the lower pH range less than 3.0, yield loss acidity in simulated acid rain varied among plant species. The yield of rice was not reduced even at pH 2.5.View full abstractDownload PDF (925K) -
Observation toward a Better UnderstandingThe Executive Committee of Sectional Meeting on Lo1994 Volume 50 Issue 2 Pages 129-133
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
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Eiji GOTO1994 Volume 50 Issue 2 Pages 135-139
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
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Makio Hayashi1994 Volume 50 Issue 2 Pages 141-144
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
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Hiroshi Seino1994 Volume 50 Issue 2 Pages 145-148
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (659K) -
Marginal Value of Storm and Heavy RainfallWorking Group of Meteorological Improvement Studie1994 Volume 50 Issue 2 Pages 149-151
Published: September 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (436K)
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