| Project/Area Number |
12660055
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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 | Tohoku University |
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Principal Investigator |
NANZYO Masami Tohoku University, Graduate School of Agricultural Science, Professor, 大学院・農学研究科, 教授 (60218071)
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| Project Period (FY) |
2000 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | volcanic ash / apatite / re-vegetation / phosphorus / phosphate rock / chelate / organic acid / pH |
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| Research Abstract |
Apatite in unweathered volcanic ash is one of the natural phosphorus resources in the natural and agricultural ecosystems. Reactions of apatite with active Al and Fe in soil depended much on pH than the kind of active Al and Fe. At the higher final pH 4.5, apatite reacted little with active Al and Fe while phosphate was sorbed much by the active Al and Fe at the lower pH region than 4.5. Aciive Fe tended to sorb slightly more phosphate than active Al at pH region higher than 4.5. Citrate and oxalate showed higher phosphate dissolution than active Al and Fe at this pH region. Rough surface was observed using scanning electron microscope after the treatment citrate. Considering these results, plants having either acid exudation or chelating organic acid exudation properties from plant roots are promising for using apatite in volcanic ash.
Although plant-available phosphate content of pyroclastic flow deposit from Unzen volcano, Japan was small as much as several tens mg P2O5 kg-1, fine pa
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rticle-size fraction showed higher available phosphate content and available phosphate level increased with pulverizing of the coarse fractions. These properties were similar to other neutral to acidic tephras. Phosphorus-rich particle found in the heavy fine to medium sand fraction showed Ca/P atomic ratio close to that of apatite and these were identified as apatite. The apatite particles occurred in the Unzen pyroclastic flow deposit as discrete particles or inclusion in other minerals. The increase in available phosphate with grinding is due to exposure of apatite inclusion in other minerals.
Growth of pigeon pea and chick pea, that have chelating organic acid exudation and grew almost ordinarily in the Mt. Pinatubo volcanic ash with N fertilizers, did not grow well possibly due to its low available phosphate content.
Buckwheat showed better growth in the pyroclastic flow deposit from Unzen volcano. The main reason was high acid exudation ability when it was grown with an ammonium fertilizer. Less
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