土壌の物理性
Online ISSN : 2435-2497
Print ISSN : 0387-6012
86 巻
選択された号の論文の6件中1~6を表示しています
  • 加藤 哲郎, 米田 和夫
    2001 年 86 巻 p. 1-9
    発行日: 2001年
    公開日: 2021/10/27
    ジャーナル フリー
    1. The effect of combination of cultivated soil depth and amount of fertilizer on vegetable crops yield and soil The experiments had two levels of fertilizers, standard and 1.5 times the standard, and three levels of cultivated soil depth, 15cm, 25cm and 40cm. 1) The yield of broccoli {Brassica oleracea L.) was larger in the deep cultivated soil plots, but yield was decreased in the 1.5 times fertilizer plot. 2) The yield of Komatsuna (Brassica rapa L.) in the deep cultivated soil plot with the standard fertilizer was greater than 1.5 times fertilizer plot. 3) In the 1.5 times fertilizer plots, leaching of CaO and MgO was high, pH of soil was low, and the EC was high. 4) Available P was lower in the deep cultivated soil regardless of the amount of fertilizers. 6) In cultivated soil depth of 15cm and 25cm, It was suggested that standard fertilization quantity was too many. 2. The effect of combination of cultivated soil depth and a low amount of fertilizer on vegetable crops yield and soil. The experiments had two levels of fertilizers, standard and 0.8 times the standard, and three levels of cultivated soil depth, 15cm, 25cm and 40cm. 1) Cucumber (Cucumis sativus L.) was increased the yield from the 0.8 times level in the shallow cultivated soil plots, but the yield in the deep cultivated soil was higher in the standard fertilizer. 2) The yield of broccoli in the 0.8 times fertilizer plot was larger in the shallow cultivated soil plots, and did not differ much in the deep cultivated soil plot. 3) The EC value did not differ much in the cucumber experiments, but they were clearly higher in the 0.8 times fertilizer plots in broccoli. 4) Available P, pH and the bases tended to be higher in the shallow cultivated soil plots. 5) Available P and the bases were low in the 0.8 times fertilizer plots, but they tend to be accumulated in the standard fertilizer plots.
  • 加藤 亘, 小林 裕志, 杉浦 俊弘, 馬場 光久
    2001 年 86 巻 p. 11-18
    発行日: 2001年
    公開日: 2021/10/28
    ジャーナル フリー
    牛スラリー施用が上壌の物理性に与える影響のうち,団粒形成にっいての検討は少なく,団粒形成因子としての牛スラリーの役割を明らかにする必要がある.本研究では,その基礎実験として,植物根や上壌生物の影響のないケイ砂培地に濃度の異なるスラリーを投ザし,力学的な試験によってケイ砂粒了-の結合の強さを求めた. ケイ砂粒子の結合の強さは,スラリーとケイ砂の混合体を風乾後,一軸圧縮試験とスレーキング試験から検討した.スラリーとケイ砂の混合体の力学的な特徴を次に示す. ① 風乾処理によりスラリー中の有機物がケイ砂粒子を接着して固結する. ② スラリーの全蒸発残留物濃度の增加にともない一軸圧縮強さは增加する. ③ 24時間の静水中への浸漬においてスレーキング耐性を示す. ④ 再湿潤処理後の一軸圧縮強さは,風乾時の半分以下に弱まる. 以上の結果から,スラリー屮に含まれる有機物は,ケイ砂粒子間の接着物質として作用し,湿潤乾燥の繰り返しにより耐水性団粒を形成する可能性を持つと考えられる.
  • 金 原台, 矢橋 晨吾
    2001 年 86 巻 p. 19-24
    発行日: 2001年
    公開日: 2021/10/28
    ジャーナル フリー
    We investigated the fundamental physical and chemical properties of dredged soils (hedoro) taken from Haneda, Kasumigaura, Saga and Ohbagawa. We also investigated the changes of consistency index, pF-moisture curves and saturated hydraulic conductivity of Haneda and Kasumigaura soils at different drying stages. The results are summarized as follow ; 1. There were large variations in fundamental physical and chemical properties of dredged soils collected from different places. 2. In air - dried soils, hydraulic conductivity increased while increasing in dry density. 3. The drying caused an irreversible effect on consistency index, pF-moisture curves and saturated hydraulic conductivity. These facts indicate that the effects of drying on these properties are considered to be resulted from irreversible changes in the structural status of the soil.
  • 吉田 正則
    2001 年 86 巻 p. 25-37
    発行日: 2001年
    公開日: 2021/10/28
    ジャーナル フリー
    Hysteretic behavior between soil matric potential and water content relationship is reviewed in concern with its models. Mechanistic models, namely (1)inkbottle model,(2) contact angle model, (3) air entrapment and solution/dissolution model, and ⑷ capillary condensation model, have been proposed to explain the hysteresis. However, none of these models has explained quantitative aspects of the hysteresis so far. Alternatively, quantitative models involving empirical ones, namely (1)domain model coupled with similarity hypothesis, (2) interpolation model,(3)linear model, and (4) parameter scaling model, were incorporated into numerical simulation of soil water dynamics. In these models, the domain model with similarity hypothesis appears to be the most appropriate for the reasons that which has theoretical background, good estimation in high hydraulic conductivity area, and no “pumping” effect To clarify effects of soil water hysteresis under in situ conditions and to improve the quantitative models applicable to long-term monitoring of soil water movement are in great necessity.
  • 磯部 勝孝
    2001 年 86 巻 p. 39-46
    発行日: 2001年
    公開日: 2021/10/29
    ジャーナル フリー
    The relation between plant root and mycorrhiza and the soil environment were reviewed. The existence of root and mycorrhiza in soil promoted the aggregation of soil and increased available nutrition. As a result, it improved soil productivity and prevented soil erosion. The colonization of mycorrhizal fungi and sporulation was affected by soil moisture and soil structure. For the germination of spore, the oxygen was necessary. On the other hand, carbon dioxide promoted the spore germination of mycorrhizal fungi.
  • 野口 正二
    2001 年 86 巻 p. 47-55
    発行日: 2001年
    公開日: 2021/10/29
    ジャーナル フリー
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