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Volume 49, Issue 4
Displaying 1-14 of 14 articles from this issue
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An Application to Estimate Species Composition in a Mixed Pasture FieldHiroshi SHONO, Masumi OKADA, Seiichiro HIGUCHI1994 Volume 49 Issue 4 Pages 227-235
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe purpose of the present study was to evaluate the applicability of three methods of texture analysis (Spatial Gray Level Dependence Method: SGLDM, Gray Level Run Length Method: GLRLM and Power Spectrum Method: PSM) to photographic images from close distance. These methods have been applied primarily to satellite images. For an example, a 1m×1m ground surface covered by a mixture of orchard grass and white clover was photographed, and the photographic image was divided into 49 square blocks. The composition of the 2 species was estimated for each block.
The image of the mixed pasture was characterized by the mixed texture of the 2 species with very different leaf shapes and by the heterogeneous texture due to the roughness of the canopy surface.
Most of the textural features related fairly well to the composition of the 2 species for all the three different methods. They, however, showed a significant difference in stability and linearity.
In the estimation of a dominant species, classification accuracy exceeded 80% in all the methods. In a comparison between the observation and estimation of the species composition, the coefficient of correlation exceeded 0.8. In particular, GLRLM showed the highest value of 0.918 among the three methods. Standard error of estimation was 11.6% in GLRLM, 16.0% in SGLDM and 16.7% in PSM.View full abstractDownload PDF (4655K) -
Concept with Preliminary TestYoshio INOUE, M. Susan MORAN, Paul J. PINTER JR.1994 Volume 49 Issue 4 Pages 237-246
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSA new concept for estimating potential and actual values of daily transpiration rate of vegetation canopies is presented along with results of an initial test. The method is based on a physical foundation of spectral radiation balance for a vegetation canopy, the key inputs to the model being the remotely sensed spectral reflectance and the surface temperature of the plant canopy. The radiation interception or absorptance is estimated more directly from remotely sensed spectral data than it is from the leaf area index. The potential daily transpiration is defined as a linear function of the absorbed solar radiation, which can be estimated using a linear relationship between the fraction absorptance of solar radiation and the remotely sensed Soil Adjusted Vegetation Index for the canopy. The actual daily transpiration rate is estimated by combining this concept with the Jackson-Idso Crop Water Stress Index, which also can be calculated from remotely sensed plant leaf temperatures measured by infrared thermometry. An initial demonstration with data sets from an alfalfa crop and a rangeland suggests that the method may give reasonable estimates of potential and actual values of daily transpiration rate over diverse vegetation area based on simple remote sensing measurements and basic meteorological parameters.View full abstractDownload PDF (1258K) -
Taichi MAKI, Borong PAN, Mingyuan DU, Kenji UEMURA1994 Volume 49 Issue 4 Pages 247-255
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSEffects of double line windbreaks on climatic elements, sand accumulation and crop are evaluated at arid or dry land of Turfan, Northwest China. Main results are as follows:
(1) The effects on wind speed, temperatures and humidity are accumulated by the increase of windbreak line.
(2) The increase and decrease of surface soil temperature are small by shade of sunshine in the daytime and by small radiation cooling in the nighttime based on windbreak, respectively.
(3) Relative humidity increased from 10 to 15% based on effects of transpiration from tree leaves and of evaporation from soil, particularly at weak wind night in summer. The effect is accumulated by increases of windbreak line and width.
(4) Variations of air temperature and humidity seem to be generally symmetrical patterns in particular, their characteristics and frequency are significant and high under the dry condition. The increasing and decreasing effects on air temperature by windbreak are based on decreasing wind and use of latent heat of transpiration, respectively, therefore, the effects are canceled each other and patterns are not changed in appearance.
(5) The climatic improvement by windbreak is very important at dry land. As windbreak trees seem to be streamline shape in relation to strong wind, dryness, sand accumulation, etc., the recover of wind is fast and the effective region is relatively small. The construction of ideal-shape windbreak needs earnest effort under the severe climatic condition.
(6) The fine-dense leaves and branches of tamarisk are effective on sand accumulation, and preventions of wind erosion and drifting sand. As the elongation of tamarisk is large, the tree can grow even if it is covered by sand. Tamarisk is suitable for windbreaks at dry land.
(7) Though the maximum effect on crop height is found from 2 to 5 H (maltiple distance of windbreak height) and the effect destroys relatively fast under the severe dry condition, windbreaks are indispensable to crop cultivation in dry land.View full abstractDownload PDF (3052K) -
Atsushi KANO, Kimitoshi SAKAGUCHI1994 Volume 49 Issue 4 Pages 257-262
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSWe have developed a technique to stimulate flower shoot emergence of Phalaenopsis plants, which requires temperature at about 20°C for flower shoot emergence in the summer. In a nonair-conditioned greenhouse, mature Phalaenopsis plants were placed between guide rails on which an insulated cabinet moved back and forth. The cabinet completely covered the plants from 10:00 to 16:00, when air temperature and irradiance in the greenhouse were high, and from 19:00 to 5:00 (night). When it was colsed, air temperature inside the cabinet was keps at 20°C. During other periods of the day, the plants were exposed to ambient greenhouse conditions.
The treatment started July 12, 1992 and continued for 12 weeks. The Phalaenopsis plants continued their growth and showed leaf area increases similar to plants in the greenhouse without the treatment. Flower shoot emergence was stimulated by the treatment, while no emergence was observed without the treatment. The number of florets per plant and number of days to anthesis were comparable to those observed when other methods are employed for flower shoot initiation, such as temporary relocation of plants to a coolar place and air-conditioning of the entire greenhouse.
This technique can be applied to greenhouse cooling. When the cooling area is covered by aluminum coated film, the heat load of air-conditioning due to radiand energy will be reduced during the daytime.View full abstractDownload PDF (749K) -
Yasuyuki AONO, Yukio OMOTO1994 Volume 49 Issue 4 Pages 263-272
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSThe change of the monthly mean temperature for March since the 11th century is estimated from the records of cherry blossom in old documents. The dates given as cherry blossom festivals in old diaries and chronicles are assumed as full flowering dates of Prunus jamasakura, one of the native cherry tree species of Japan. The temperatures are estimated by means of DTS method, which has been used to estimate flowering date from temperature data. It is shown that computations for the recent 40 years proved that the decadal average values of the March temperature may be obtained by the method for P. jamasakura with the accuracy of 0.1°C of the root mean square error.
It is shown that the entire study period can be roughly divided into three subsections. In the first period (the 11-13th centuries), the March appeared to be generally very warm compared with other periods, however, accuracy of the estimated values are rather poor because decadal averages are computed from relatively small number of years due to missing of records.
For the second period (the 14-16th centuries), there was a period of warming of 2°C from 1470's to 1610's, otherwise the decadal averages suggest large fluctuations, at least partly attributed to poor quality of full flowering data of P. jamasakura.
For the third period (the 17-20th centuries), temperatures generally tend to be estimated in low values, especially estimations in 1690-1710's and 1810-30's continued to the present is noticeable. The rise amounts to 3.4°C seems due both to urban warming and larger scale warming over the central Japan roughly the same degree.View full abstractDownload PDF (1382K) -
Takashi HIRANO, Kazuo SEKI, Makoto KIYOTA, Ichiro AIGA1994 Volume 49 Issue 4 Pages 273-277
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSCucumber plants were grown in the pots cantaining the soil covered with volcanic ash from Mt. Unzen-Fugendake, and the concentration of CO2 and O2 in the soil was measured during the cucumber growth. Diffusion of O2 was also measured in the volcanic ashes from Mt. Unzen-Fugendake and Mt. Sakurajima, and in the soil. The O2 diffusion coefficients were much smaller in the volcanic ashes than in the soil. In the rhizosphere, the concentration of CO2 increased and that of O2 decreased under the soil cover with the volcanic ash. This was attributed to the slower exchanges of CO2 and O2 between the atmosphere and the soil through the volcanic ash layer. The cucumber growth in the pots with the soil cover was slower than in the control pots. The increased CO2 concentration in the rhizosphere may be the cause of the growth reduction.View full abstractDownload PDF (656K) -
Hiroshi HAMAMOTO1994 Volume 49 Issue 4 Pages 279-283
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSEffects of a rowcover and a mulching on plant growth and rhizospheric environment (soil hardness, soil moisture and soil temperature) were examined. Spinach (Spinacia oleracea L.) was used and tested on late July, 1991 and mid February, 1992. Plants were covered with a spunbonded polypropylene fabric when two leaves unfolded. Following environment were measured through the experiment; air temperature, soil temperature at a depth of 10cm, matric potential of soil water at a depth of 15cm and penetration resistance of 10cm thick soil layer.
Matric potential of soil water and penetration resistance of soil were decreased by both treatments, and soil temperature was increased only in spring. Plant growth was enhanced by the rowcover than by mulching in spring. Differences of plant growth between the rowcover and the mulching sections showed that the modification of atmospheric environment by the rowcover is effective for spinach growth, but the modification for rhizospheric environment also affect to the spinach growth.View full abstractDownload PDF (624K) -
Haruhiko YAMAMOTO, Yoshinori SUZUKI, Seiji HAYAKAWA1994 Volume 49 Issue 4 Pages 285-290
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (4953K) -
Hitoshi HONJO, Toshihiko SUGIURA, Hiroshi SUGAYA1994 Volume 49 Issue 4 Pages 291-296
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
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Katsuyoshi WATANABE1994 Volume 49 Issue 4 Pages 297-300
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
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Snow Damage and Utilization of SnowWorking Group of Meteorological Improvement Studie1994 Volume 49 Issue 4 Pages 301-303
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
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Kenji Omasa1994 Volume 49 Issue 4 Pages 305-306
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
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[in Japanese]1994 Volume 49 Issue 4 Pages 307
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (153K) -
[in Japanese]1994 Volume 49 Issue 4 Pages 307a-308
Published: March 10, 1994
Released on J-STAGE: February 25, 2010
JOURNAL FREE ACCESSDownload PDF (219K)
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