| Autor: |
He, J. Z., Gilkes, R. J., Dimmock, G. M. |
| Zdroj: |
Australian Journal of Soil Research; 1998, Vol. 36 Issue: 3 |
| Abstrakt: |
Very sandy and sometimes seasonally inundated humus podzols of the Bassendean soil association in southwest Australia experience severe leaching of fertiliser P with consequent eutrophication of waterways. P sorption by these soils is mostly minimal and is primarily due to the podzol Bh horizon. The consequence of seasonal drying of profiles under the prevailing Mediterranean climate on the P sorption capacity of these B horizon materials is not known. The e®ects of air-drying on P sorption were studied for 3 sandy podzols using samples from entire soil profiles collected in winter (wet) and summer (dry). Results confirm that the surface and near surface horizons (i.e. A and E horizons) of these soils have very low P sorption capacities. Only some B horizon materials exhibit substantial P sorption and this is mostly due to allophane, with minor contributions from extractable Fe forms, organic carbon, and clay. Air-drying during summer and in the laboratory increased P sorption of B horizon materials by up to 120% compared with field-moist samples. The difference in P sorption between air-dried samples and the field-moist samples decreased for long reaction times. phosphorus leaching, seasonal change, allophane. |
| Databáze: |
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