Phosphorus extractions under air-dried, oxidized and reduced conditions for some rice soils from KADA
A laboratory study was conducted for extracting available soil P by six chemical methods under air dried, oxidized, and reduced conditions for some rice soils. A total of eight soil series taken from Kemubu Agricultural Development Authority (KADA) were investigated. The ranking of the extractants u...
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| Main Authors: | , |
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| 格式: | Journal Contribution |
| 語言: | English |
| 出版: |
2017
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| 主題: | |
| 在線閱讀: | http://agris.upm.edu.my:8080/dspace/handle/0/13214 |
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| 總結: | A laboratory study was conducted for extracting available soil P by six chemical methods under air dried, oxidized, and reduced conditions for some rice soils. A total of eight soil series taken from Kemubu Agricultural Development Authority (KADA) were investigated. The ranking of the extractants used in terms of their extracting strength for the reduced condition was as follows: Olsen > Bray No. 2 > Double Acid > Kapp's Texas Buffer > Bray No. 1 > 0.1N HCl. The mean P extracted by Olsen, Bray No. 2 and Double Acid were 18.10, 14. 75 and 12.01 ppm respectively. All the six chemical extractants demonstrated that the status of extractable P for KADA rice soils is low. Among these extractants, it appeared that Bray No. 2, Double Acid and Olsen methods were capable of extracting P consistently from all the eight soil series under the three conditions investigated. When compared to oxidized condition, reduction process significantly increased the extractable P except in O.l'N HCl and Bray No. 1 extractants. The same pattern was observed for the air-dried condition except in Bray No. 1 where there was a significant decrease instead. The oxalate extractable iron in the three conditions were correlated with the respective P values. The highest coefficient of determination was observed for the Olsen extractant in the air-dried condition (R2 = 0.8286*). For the anaerobic condition, Bray 2 extractant was the superior ones (R2= 0.6448). However, for the aerobic condition, Kapp's Texas Buffer was the highest (R2= 0.4206). |
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