| Project/Area Number |
11660065
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Plant nutrition/Soil science
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| Research Institution | KOCHI UNIVERSITY |
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Principal Investigator |
SAKURAI Katsutoshi FAC.AGRIC., KOCHI UNIV.PROFESSOR, 農学部, 教授 (90192088)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Sota FAC.AGRIC., KOCHI UNIV.ASSIST.PROFESSOR, 農学部, 助手 (10304669)
KANG Yu-mei FAC.AGRIC., KOCHI UNIV.ASSOC.PROFESSOR, 農学部, 助教授 (70284429)
IWASAKI Kozo FAC.AGRIC., KOCHI UNIV.ASSOC.PROFESSOR, 農学部, 助教授 (40193718)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1999: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | RHIZOSPHERE ECOLOGY / INTERGRADE CLAY MINERALS / HEAVY METALS / BORON / LOW MOLECULAR WEIGHT ORGANIC ACID / MICROBIAL BIOMASS / MYCORRHIZA / SIBA-GRASS LAND / 根圏 / 生態系 / セレン |
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| Research Abstract |
The research methodology for rhizosphere ecology was investigated by various aspects ;
1) Using the rhizobox system, effectiveness of the commercial fertilizer containing endomycorrhiza was evaluated in terms of nutrient intake of sunflower. Mycorrhizal infection caused an increase in phosphorus absorption together with Fe. This phenomenon could be interpreted as the dissolution of Fe-P compounds, which is hardly dissolved in soils. Several phosphatases excreted by plant roots or mycorrhiza would have promoted it.
2) Methyl bromide will be forbidden to use as soil fumigation in 2005, which is a quite important chemical in Kochi. We try to evaluate the effectiveness of steam fumigation as an alternative method that does not cause any detrimental effect chemically. We found that the steam fumigation method did not affect the biodiversity of microorganisms. However the dissolution of manganese seemed to make a damage to the plants.
3) The content of boron as a beneficial microelement in soil
… More
s was determined using several types of agricultural soils in Kochi. Total boron content is within a common level found in Japan. However, available boron in soils was in a deficient level. The former is hardly released into the environment, on the other hand, the latter will be easily flew down to the environment when applied as a fertilizer. We need to pay attention to the application of fertilizer including boron.
4) At the reclaimed grass land, species sosiba japonica can cover the soil surface after 10 years. At this timing, a hard pan layer is being formed, but the soil structure is not well developed. Further 10 years made the good soil structure (granular) which caused a significant improvement in water drainage as well as water holding property. The abundance and diversity of soil microorganisms and also low molecular weight organic acids fluctuated greatly in response to the soil moisture content. In conclusion, at more than 20 years after reclamation of forest land, sosiba grass land can be considered as an excellent ecosystem equivalent to the forests in terms of water and nutrient dynamics in soil environment. Conservation of water in the hilly region, therefore, could be achieved by means of the formation of good sosiba grass land. We could recommend to establish a sosiba grass land when the paddy field in a small scale on the sloping land in the mountainous region can not be maintained any more.
Rhizosphere ecosystem could be considered as a well organized or integrated natural system comparable to the whole plant ecosystem, not as a part of ecosystem. We still need further investigation sticking to rhizosphere. Less
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