Extractable aluminium, iron and manganese in mineral soils: I Dependence of extractability on the pH of oxalate, pyrophosphate and EDTA extractants
Al, Fe and Mn in two mineral soils were extracted by 0.05 M and 0.02 M oxalate and pyrophosphate and 0.02 M EDTA solutions the pH of which was adjusted to values ranging from 1.7 to 11.0. The extractability of metals tended to decrease as the pH rose and as the deprotonation of extractant acid, expr...
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| Format: | Article |
| Language: | English |
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Scientific Agricultural Society of Finland
1989-03-01
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| Series: | Agricultural and Food Science |
| Online Access: | https://journal.fi/afs/article/view/72355 |
| Summary: | Al, Fe and Mn in two mineral soils were extracted by 0.05 M and 0.02 M oxalate and pyrophosphate and 0.02 M EDTA solutions the pH of which was adjusted to values ranging from 1.7 to 11.0. The extractability of metals tended to decrease as the pH rose and as the deprotonation of extractant acid, expressed as pKa values, progressed. The reduction in extractability of metals by oxalate was rather steep at pH > 4, whereas the extractability by pyrophosphate remained moderate at a wider pH range. The extractability of metals by EDTA (pH 3.6—7.3) was lower than that by oxalate and pyrophosphate. Extractability was lower in the absence of the studied oxyacid anions and with 0.01 M KCI as the supporting electrolyte at a pH between 2 and 11 than in their presence. |
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| ISSN: | 1459-6067 1795-1895 |