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Volume 59, Issue 1
March
Displaying 1-8 of 8 articles from this issue
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Full Papers
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Haruhiko YAMAMOTO, Kiyoshi IWAYA, Yuki TAKASUArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 1-11
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSEfficiency of solar energy utilization (Eu) and efficiency of solar energy conversion (Ec) were compared and studied for panicle-weight type genotypes developed at the Chugoku National Agricultural Experiment Station, leading cultivars produced in the Chugoku region, and highyielding types developed in other countries. Furthermore, efficiency rates in solar energy utilization and conversion gathered to date have been compared with efficiency rates obtained by this author. Eu ranges from 1.37 to 1.61%, with a high efficiency rate of more than 1.55% were recorded for panicle-weight types Chugoku 113, Chugoku 116 and Hoshiyutaka, Indica-type Tainung 68 and Miliyang 23, and Japonica type Nipponbare and Koganebare. The solar energy utilization rate for grain weight (Eu grain) ranged from 0.48 to 0.75%, with rate of 0.7% or higher for Chugoku 118, Hoshiyutaka, Miliyang 23, Nipponbare and Koganebare. Ec was as high as 2.98, 2.83 and 2.68% for Nipponbare, Hoshiyutaka and Chugoku 118, respectively. The high Ec rate for panicle-weight types is likely to be caused by high radiation absorption, due to high absorption of each genotype, and a high level of total integrated solar radiation. Radiation use efficiency (RUE) was 1.98 g/MJ, 1.97 g/MJ and 1.85 g/MJ for Hoshiyutaka, Nipponbare and Chugoku 118, respectively. The difference was not accepted in the genotypes used for the experiment. In order to raise Ec and RUE, a leaf inclination angle is large and a plant type with the light-intercepting characteristics and high LAI is an ideal. Furthermore, high-yielding productive capacity needs to maintain a high canopy absorption by maintaining the SPAD value of a leaf with the topdressing of a ripening periodView full abstractDownload PDF (704K) -
Din Ara WAHID, Etsuji ISHIGURO, Tomohide SHIMOTASHIRO, Shinsaku HIRAYA ...Article type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 13-21
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSIn recent years, many studies have been reported on remote sensing techniques in agricultural production to utilize the advantage of simultaneous and wider monitoring capability of satellite data. Several studies have been conducted to develop links between spectral reflectance and temperature for traditional paddy rice cultivation. In our study to characterize the spectral reflectance of paddy rice (Oryza sativa L., cv. Hinohikari) with the lengthening growing days, the spectral reflectance of rice leaves from 400 nm to 1, 100 nm wavelength range was acquired with a handheld spectroradiometer. A wide range of nitrogen (N) was applied in experimentally field-grown paddy rice. To develop a growth model for paddy rice we analyzed physical parameters, spectral reflectance and fractional photosynthetically active radiation (fPAR). The following conclusions were drawn: (1) Different spectral characteristics were observed during the growth stages for different N-treatments; (2) Detection of significant differences between N-treatments was realized with the ratio vegetation index (RVI) at full heading stage; (3) Red edge points poorly correlated with leaf area index (LAI), dry weight (DW) and fPAR; (4) The R830/R550 ratio highly correlated with LAI and DW during the entire growing season. The prediction accuracy of fPAR was also very high using the R830/R550 ratio. Though our study accounts for only limited factors, it was concluded that growth models for monitoring paddy rice could be based on RVI and the R830/R550 ratio.View full abstractDownload PDF (525K) -
Akihiko ITOArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 23-34
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSThis paper presents a high-precision map of terrestrial net primary productivity (NPP) in East Asia (20° to 60° N, 100° to 170° E; 10.4×106km2), using a high-resolution process-based model (Sim-CYCLE). Using recent datasets of land cover (46 types), soil, and topography, an NPP map of East Asia was obtained, at the spatial resolution of as high as 5-minutes: i.e., 6 to 12 times finer than previous ones. The calculated NPP values were compared with observations and several other models, to verify the model validity. Total annual NPP, 5.06 Pg C, was close to those with empirical models, and seasonal variation in NPP was consistent with that based on remote sensing data. Based on the estimated NPP, radiation-use efficiency (average 0.28 g C MJ-1 PAR) and water-use efficiency (average 1.54 g C kg-1 evaporation) were calculated. The new mapping was especially effective for retreiving spatial heterogeneity due to steep topography and intensive land-use conversion, which was overlooked in previous coarse mappings. Compared with other approaches based on empirical relationships or satellite data, the process-based model is advantageous for exploring whole carbon dynamics (i.e. net ecosystem production) and future projection.View full abstractDownload PDF (2369K) -
Hisashi KON, Yusuke YAMAMOTO, Nobuhiro MATSUOKA, Michiaki OKANOArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 35-41
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSMuch research has been done on the depletion of the ozone layer and consequent increase in ultraviolet B radiation (UV-B). In this study, a UV-B mesh map was compiled to show the distribution of radiation in Japan. Data on daily solar radiation and daily UV-B radiation observed in Sapporo, Tateno, Kagoshima and Naha from 1991 to 1997 were used, as well as the existing mesh data of solar radiation. First, ratios of daily UV-B to daily solar radiation were calculated for four observation sites, and then a sinusoidal curve was fitted to the annual changes in ratio for each site. The coefficients (amplitude, phase lag and mean value) of the sinusoidal functions were respectively presented as linear functions of latitude. The coefficients of correlations between the coefficients of the function and latitude were higher than 0.86. The ratio of UV-B to solar radiation can thus be calculated for any latitude by using the sinusoidal function whose coefficients are a function of latitude. Finally, monthly and annual UV-B mesh map for 1 km×1 km were obtained by multiplying this ratio by the existing mesh data of solar radiation. The procedure was done by using GTOPO30 and GRASS5.0 for the region of Japan. The state of the changes agreed well with the observed values and the standard error of estimated UV-B was 9.6%.View full abstractDownload PDF (1466K) -
Toshihiko SUGIURA, Daiyu ITO, Haruyuki KURODA, Hitoshi HONJOArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 43-49
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSThe effects of high temperature and subzero temperature on endodormancy completion in flower buds of Japanese pear (Pyrus pyrifolia Nakai cv. ‘Kosui’) were investigated using potted trees. The trees were chilled in temperature-controlled (daily cycles of 6/6°C, 6/−3°C, 6/−6°C, 18/6°C, 21/6°C and 24/6°C) dark rooms from late Octoer or from early November. After chilling for various lengths of time, they were forced in a growth chamber adjusted to 25°C. The endodormancy completion was judged from the percentage of flowering and normal flower after forcing. Flower buds were released from endodormancy by exposure to 6°C for about 780 hours. It was clear that chilling efficiency at −3°C fell within the range of 1/2-1/3 of that at 6°C, while at −6°C, the endodormancy was not complete. High temperatures of 21°C or 24°C negated a part of the cumulative effect previously received from the chilling treatment, but 18°C did not negate itView full abstractDownload PDF (666K)
Short Papers
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Manabu NEMOTO, Masato SHINODA, Hongbo JUArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 51-58
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSIn this paper, we validate the simple water balance model incorporated in the Carnegie Ames Stanford Approach (CASA) model with hourly soil moisture observations at a semi-arid site in the Ordos plateau of Inner Mongolia. The CASA model is widely used for estimating large-scale net primary productivity (NPP) based on satellite data. The results indicated that the soil moisture submodel of the CASA model did not simulate absolute values and seasonal changes observed at the Ordos site in Inner Mongolia. In order to realistically estimate soil moisture, we considered the following two points: (1) the time interval of the model is set to be daily instead of monthly and (2) a new scheme of evaporation efficiency for daily calculation that produces a wide range of evaporation variation. The soil-moisture model proposed by the present study will be useful for estimating precise NPP for semi-arid land, based on process models.View full abstractDownload PDF (911K)
Review Papers
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Isamu NOUCHIArticle type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 59-67
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSPhotochemical oxidant pollution and related occurrences of plant injury have occurred in Japan every year since 1969-1970. Crop injury by photochemical oxidants (mainly ozone) is directly connected with agricultural economic loss. Especially, the marketable values of damaged leafy vegetables are greatly reduced, causing drastic economic losses. Five methods of agriculture technology for avoiding damage resulting from ozone are considered: (1) inherited resistance properties of crops; (2) fertilizer management; (3) treatment with specific chemicals; (4) biotechnological activation of defense genes; and (5) in-facilities cultivation. However, until now these methods only offer a temporary countermeasure, providing limited protection and are useful only against occurrence of mild injuries.View full abstractDownload PDF (969K) -
Yoshinobu HARAZONO, Takashi HIRANO, Nobuko SAIGUSA, Yoshikazu OHTANI, ...Article type: Others
Subject area: Others
2003 Volume 59 Issue 1 Pages 69-80
Published: 2003
Released on J-STAGE: March 31, 2004
JOURNAL FREE ACCESSContinuous long term micrometeorological CO2 flux observation has become an essential component to accurate determine CO2 uptake in terrestrial ecosystems after COP3. Because the intergovernmental agreement on CO2 emission control (Kyoto protocol) allows each country to subtract the annual accumulation of CO2 uptake by their ecosystems from the total anthropogenic CO2 emission. Hence, the demands to determine the CO2 uptake more accurately at the ecosystem level, and to make the long term CO2 flux observation a major research within multidisciplinary study fields such as ecology, biology, meteorology and agriculture have been increased significantly. Several flux observation sites have been operating in ecosystems of North America and Europe since 90’s. These sites were initially independent research projects, but were later organized into networks such as AmeriFlux and EUROFLUX. FLUXNET was also established to enhance the understanding of ecosystem CO2 exchange including data exchange and to promote the measurement methodology among the networks. AsiaFlux was established in fall of 1999 as part of a flux observation research network in Japan and some Asian countries. The Study Group for Flux Measurement and Evaluation (S-FluME), the Society of Agricultural Meteorology of Japan (SAMJ) was organized to enhance the research activities of flux observations, and has been contributing to the activities of AsiaFlux.This paper reviews the development of theoretical and practical methodology of flux observation and discusses topics that arose from previous long term flux observations. Some suggestions and comments to improve the flux determination are also shown.View full abstractDownload PDF (985K)
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