Journal of the Japanese Society of Soil Physics
Online ISSN : 2435-2497
Print ISSN : 0387-6012
Volume 86
Showing 1-6 articles out of 6 articles from the selected issue
  • Tetsuo Kato, Kazuo Yoneda
    2001 Volume 86 Pages 1-9
    Published: 2001
    Released: October 27, 2021
    JOURNAL FREE ACCESS
    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.
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  • Wataru Kato, Hiroshi Kobayashi, Toshihiro Sugiura, Mitsuhisa Baba
    2001 Volume 86 Pages 11-18
    Published: 2001
    Released: October 28, 2021
    JOURNAL FREE ACCESS
    We investigated the strength of air-dried mixtures of sand and cattle slurry using unconfined compression and slaking tests, and obtained the following results :1.The sand and cattle slurry mixtures hardened when dried. 2. A significant correlation was found between unconfined compression strength and mixed slurry concentration. 3. Air-dried samples showed waterstability. 4. The unconfined compression strength of re-wetted samples (moisture content about 300 gkg-1) was less than that of air-dried samples. These results show that the organic matter in cattle slurry facilitates aggregation.
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  • Wontae Kim, Shingo Yabashi
    2001 Volume 86 Pages 19-24
    Published: 2001
    Released: October 28, 2021
    JOURNAL FREE ACCESS
    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.
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  • Masanori Yoshida
    2001 Volume 86 Pages 25-37
    Published: 2001
    Released: October 28, 2021
    JOURNAL FREE ACCESS
    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.
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  • Katsunori Isobe
    2001 Volume 86 Pages 39-46
    Published: 2001
    Released: October 29, 2021
    JOURNAL FREE ACCESS
    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.
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  • Shoji Noguchj
    2001 Volume 86 Pages 47-55
    Published: 2001
    Released: October 29, 2021
    JOURNAL FREE ACCESS
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