農業気象
Online ISSN : 1881-0136
Print ISSN : 0021-8588
ISSN-L : 0021-8588
49 巻, 4 号
選択された号の論文の14件中1~14を表示しています
  • 牧草混生群落の草種割合推定を例として
    庄野 浩資, 岡田 益己, 樋口 誠一郎
    1994 年 49 巻 4 号 p. 227-235
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    The 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.
  • 理論と予備的検証
    井上 吉雄, M. Susan MORAN, Paul J. PINTER JR.
    1994 年 49 巻 4 号 p. 237-246
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    リモートセンシングによって植物個体群からの日蒸散量のポテンシャルおよび実際の値を評価するための新しい方法論を提示し, 実測データによる予備的検討を行った。本方法は, 植物個体群のポテンシャルな蒸散量が主に吸収放射量によって規定されており, かつ個体群の放射吸収能は葉面積指数から求めるよりも分光学的な遠隔計測によってより直接的に評価できるとの考え方に基づいている。すなわち本方法では, 遠隔計測される反射スペクトルから求めた植生指数 (SAVI) と日射量からポテンシャルな蒸散量を求め, さらに, 熱赤外放射測温に基づくストレス指標 (CWSI) を組み込むことによって, ストレス状態と実蒸散量を同時に評価する。各種の灌漑処理を行ったアルファルファ圃場, および自然草地において測定した反射スペクトル計測, 赤外線放射測温, ライシメータ, 渦相関法, および植物サンプリングによるデータを用いた予備検証の結果, 本手法の概念に基づいて, 分光データと基本的な微気象データの計測情報から, 広域にわたる植生のポテンシャルおよび実際の日蒸散量を評価できる可能性が示唆された。
  • 真木 太一, 潘 伯栄, 杜 明遠, 上村 賢治
    1994 年 49 巻 4 号 p. 247-255
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    Effects 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.
  • 狩野 敦, 坂口 公敏
    1994 年 49 巻 4 号 p. 257-262
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    We 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.
  • 青野 靖之, 小元 敬男
    1994 年 49 巻 4 号 p. 263-272
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    The 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.
  • 平野 高司, 関 和雄, 清田 信, 相賀 一郎
    1994 年 49 巻 4 号 p. 273-277
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    Cucumber 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.
  • 浜本 浩
    1994 年 49 巻 4 号 p. 279-283
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
    ポリプロピレン長繊維不織布を用いてホウレンソウのべたがけ栽培とマルチ栽培を行い, 両被覆法の地下部環境と気温への影響を調査するとともに, 両被覆区および無被覆区における生育量を比較した。
    べたがけおよびマルチは春季には地温を上昇させ, 土壌水分の保持力を高め, 土壌の硬化を防止したが, 夏季には地温への影響はほとんどなかった。べたがけは日最高気温を高めたが, マルチは気温にはほとんど影響を与えなかった。べたがけ区とマルチ区では春季のホウレンソウの生育が無被覆区より良好で, 両被覆法による地温や土壌水分量, 土壌の膨軟性の改善が生育を促進させたと考えられた。ただし, マルチ区の生育促進効果はべたがけ区に劣った。また, 夏季の作物生育はべたがけ区のみが劣った。このことから, 軟弱野菜の生育に対するべたがけ効果は, その一部が地下部環境変化に起因するが, 地上部環境変化の影響も無視できないとみられた。
  • 山本 晴彦, 鈴木 義則, 早川 誠而
    1994 年 49 巻 4 号 p. 285-290
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 本條 均, 杉浦 俊彦, 菅谷 博
    1994 年 49 巻 4 号 p. 291-296
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 渡邊 勝吉
    1994 年 49 巻 4 号 p. 297-300
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 耕地気象改善研究部会
    1994 年 49 巻 4 号 p. 301-303
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 大政 謙次
    1994 年 49 巻 4 号 p. 305-306
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 原薗 芳信
    1994 年 49 巻 4 号 p. 307
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
  • 塚本 修
    1994 年 49 巻 4 号 p. 307a-308
    発行日: 1994/03/10
    公開日: 2010/02/25
    ジャーナル フリー
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