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Volume 60, Issue 2
June
Displaying 1-8 of 8 articles from this issue
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Kiyoshi IWAYA, Haruhiko YAMAMOTO, Seiji HAYAKAWA, Makio KAMICHIKA2004 Volume 60 Issue 2 Pages 87-94
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSThe top nitrogen content (TNC) per unit area (g m-2) is an important quantitative index of the condition of nitrogen nutrition in rice production. In this study, the rapid and simple method of estimation of TNC, with the use of the existing nondestructive analyzing instruments chlorophyll meter SPAD-502 and plant canopy analyzer (PCA) LAI-2000, was scrutinized. The analysis in the rice cultivar Nipponbare, conducted in 1997 and 1998, showed a high positive correlation (R2=0.743, P<0.01) between the SPAD reading obtained by the chlorophyll meter and the specific leaf nitrogen (SLN). The leaf area index (LAI) estimated by PCA tended to underestimate the LAI determined by actual measurement by about 20%. Still, the estimation of LAI by PCA was judged to have a sufficient accuracy as a practical technique. A high positive correlation (R2=0.866, P<0.01) was obtained between the product of the SPAD reading and LAI, and the leaf nitrogen content (LNC) per unit area (g m-2). LNC and TNC also showed a very high correlation (R2=0.988, P<0.01). The product of the SPAD reading and LAI, and TNC also gave a high positive correlation (R2=0.847, P<0.01). These results indicated that the method described in this study was effective as a simple and rapid method for the estimation of TNC per unit area.View full abstractDownload PDF (721K) -
Eduardo Jimmy Pua QUILANG, Larry GUERRA, Avelino RAMIREZ, Jose HERNAND ...2004 Volume 60 Issue 2 Pages 95-102
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSAir and water temperatures are important climatic variables influencing rice yields through the interaction of pests and nutrients. The Philippine Rice Research Institute (PhilRice) in Maligaya, central region of Luzon island, stated that the Philippines could attain rice sufficiency if farmers' average yield increases to at least 1 t/ha. It is generally said that decreasing the minimum air temperature in the rice canopy could make a yield increase possible in the Philippines. Instead, results showed that the timing of irrigation water application using a shallow tubewell pump in Maligaya could not decrease canopy air temperature. However, the temperature of the standing or flooding water in the field was reduced using pumped water or ground water irrigation compared with the conventional irrigation where water came from irrigation canals, and the lower temperature of the standing water resulted in an increase in rice yield from 7.27 to 8.58 t/ha for PSB Rc28 rice cultivar and from 3.08 to 4.02 t/ha for New Plant Type IR66106-5-3-2-3. Based on this result, this study recommends that rice growers irrigate using pumped water or ground water from 15: 00 to 17: 00 with a standing water level of 5 cm during the reproductive stage to have a lower water temperature at night for better efficiency of water and resistance to white heads.View full abstractDownload PDF (617K) -
Reiji KIMURA, Makio KAMICHIKA, Naru TAKAYAMA, Nobuhiro MATSUOKA, Xingc ...2004 Volume 60 Issue 2 Pages 103-113
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSA three-layer soil model was used for clarifying the heat balance and soil water content in the Loess Plateau, China, and applied to actual bare soil fields (Tottori Sand Dune and Shenmu District, Shaanxi Province, China). The difference between the observed and calculated evaporation per day was approximately 0.18 mm (5 W m-2) to 0.21 mm (6 W m-2). Because of its moderate mixture of sand, silt and clay, yellow loessial soil in Shenmu affects water retentivity and restriction of evaporation from the soil surface. The seasonal change of heat balance and soil water content was examined using meteorological data in Yulin near Shenmu. The annual means of sensible heat and latent heat flux were 23 W m-2 and 19 W m-2 (239 mm per year), respectively. The soil water content of the second and third layers remained comparatively high in winter.View full abstractDownload PDF (933K)
Research Notes
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Murat KACIRA, Sadanori SASE, Ozlem KACIRA, Limi OKUSHIMA, Masahisa ISH ...2004 Volume 60 Issue 2 Pages 115-122
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSDownload PDF (544K)
Full Papers (in Japanese)
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Mika SAGAWA, Kenji KURATA, Kunio TAKAHASHI, Kenichi FUKUCHI2004 Volume 60 Issue 2 Pages 123-131
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSLaser induced chlorophyll fluorescence induction kinetics provides a simple and non-destructive method for making a diagnosis of indoor plants. This study aimed at developing new parameters related to the laser induced fluorescence induction kinetics for detecting stress imposed on indoor trees mainly due to low irradiation conditions. Evaluating new parameters required only 25 s for each measurement. The new parameters referred to the shape of the second maximum in the induction kinetics. In an experiment lasting over a year using Cinnamomum camphora both outdoors and in a chamber, two of the new parameters showed clear seasonal variations for the outdoor trees and almost constant values for the indoor trees. The values for the indoor trees differed according to the light environment of each tree. These results strongly suggested that the new parameters could be applicable to practical diagnosis of indoor trees.View full abstractDownload PDF (1644K) -
Masahito UEYAMA, Takako YANO, Ken HAMOTANI, Nobutaka MONJI2004 Volume 60 Issue 2 Pages 133-140
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSThe atmosphere-forest heat exchange mechanism was investigated based on the measurement applying eddy correlation method at 3 heights above and 2 heights inside the canopy of a coniferous forest. Counter gradient or zero gradient sensible heat transport was observed inside the canopy. Cospectral analysis indicates that this counter gradient flux is caused by the high frequency eddies, suggesting that the penetrating cold temperature gusts are contributing to this phenomena. Large eddies are contributing to the co-gradient flux even in the canopy. A 2nd order turbulence closure model for a horizontally homogeneous field was applied to compare with the observation. For the wind from the valley, the observed temperature profiles and sensible heat flux agreed with the computation. However, for the wind from the ridge, the observed temperature field suggested the occurrence of drainage flows which are not expressed by the computation.View full abstractDownload PDF (2015K) -
Hitoshi YOKOYAMA, Yoshinobu HARAZONO2004 Volume 60 Issue 2 Pages 141-150
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSProtected cultivation of leather-fern in Hachijo-Island has been urged to prevent the Mottled Yellowing Syndrome (MYS) damage and to reduce the production costs. The purpose of the study was to reveal greenhouse environments that would provide good plant growth, a comfortable working environment and low-cost management, by comparing the micrometeorology and leather-fern productivity between Poly-Olefin (PO) film-covered greenhouses and the conventional net-covered greenhouses. Both greenhouses were fully covered by the same net. Field studies of leather-fern cultivation in Hachijo-Island showed that better productivity and quality of leather-fern have been provided by farmer's net-covered greenhouses than by farmer's PO-covered greenhouses. The light transmittance in the net-covered greenhouse was higher and the air temperature was lower than those in the PO-covered greenhouse. The comparative experiments using PO-covered greenhouses (PO), and net-covered greenhouses (NET), were conducted at the Hachijojima Horticultural Research Center. Air temperature and its vertical gradient in NET were lower than those in PO. Irrigation in PO was 225 mm during August and September in 1999, but 507 mm of precipitation in addition to the irrigation was supplied in NET. Air temperature and its vertical gradient in PO increased with solar radiation increase. Heat disorder in working environments for farmers did not occur in the NET, but several warning hours of heat disorder occurred in the PO as a dangerous working environment. The NET was thought to be a better system of leather-fern cultivation bringing about low costs and comfortable working environments. However, further application of fully rolled-up PO-film greenhouse system was recommended to control the soil water condition.View full abstractDownload PDF (1314K) -
Shigeto KAWASHIMA, Kazuhito MATSUO, Hiroyuki SHIBAIKE, Satoshi INOUE, ...2004 Volume 60 Issue 2 Pages 151-159
Published: 2004
Released on J-STAGE: March 10, 2006
JOURNAL FREE ACCESSGene flow from transgenic crops to related species has recently come into focus in risk-assessment studies of the ecological consequences of growing transgenic crops. This problem is especially serious in maize, as it is a representative wind-pollinated plant. We observed the hybrid percentage of maize seed and meteorological conditions for two years by using the xenia phenomenon. We examined the differences in the numbers of airborne pollen, meteorological conditions and the hybrid percentages between the two years, and discussed the effect of meteorological conditions on the hybrid percentage in the recipient maize field. The hybrid percentage at a distance from the donor field could be changed by several times depending on the meteorological conditions of the year. The spatial distribution of the hybrid percentage in the recipient field shows uneven and rugged structure. In 2001, the dispersion of pollen ended in a comparatively short term, and the chance of hybridization was low. On the other hand, in 2002, the dispersion of pollen continued for a long term, and the donor pollen dispersed to a considerable distance in the recipient maize field. The chance of hybridization was high in general, and the observed hybrid percentages showed considerably high values under natural conditions.View full abstractDownload PDF (1917K)
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