1997 Fiscal Year Final Research Report Summary
Evaluation of availability of phosphorus reserved in Andisols for high yield of crop and savings of phosphorus resources.
| Project/Area Number |
08660069
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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 |
ITO Toyoaki Tohoku University, Experimental Farm, Faculty of Agriculture, Associate Professor, 農学部・附属農場, 助教授 (10176349)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Colloidal composition / Allophanic Andisols / Nonallophanic Andisols / Total soluble inorganic phosphorus / EDTA-NaF extractable phosphorus / Anion exchange resin extractable phosphorus / pH / Al injury |
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| Research Abstract |
Phosphorus (P) fertility of Andisols was evaluated with reference to colloidal composition of soils. P sorption capacity was strongly correlated to active aluminum (allophane and Al-humus complex). Nonallophanic Andisols with major active aluminum of Al-humus complex showed a higher P sorption capacity per active aluminum than allophanic Andisols with major active aluminum of allophane. Soil available P content decreased with increasing of P sorption capacity of soil.
Total soluble inorganic P reserved in soil was extracted by EDTA-NaF solution. Plant absorbed greater amounts of P from allophanic Andisol than nonallophanic Andisol with equal level of total soluble P and available P (Truog and Bray methods). Nonallophanic Andisol needed more available P for good plant growth with compared to allophanic Andisol. Allophanic Andisol showed higher value of Truog-P and anion exchange resin extractable P than nonallophanic Andisol with equal amount of total soluble P.However, nonallophanic Andisol showed higher value of Bray-P and acetic acid extractable P than allophanic Andisol with equal amount of total soluble P.It was concluded that the accurate evaluation of P availability of Andisols must be conducted by extraction methods in consideration for soil colloidal composition.
Plant available P decreased in nonallophanic Andisol with low pH less than 5.3.Soil available P contents did not change within the pH range of 4.5 to 7.0. In low pH,the inhibition of root elongation by Al injury caused the reduction in P absorption of plant.
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