Effects of pretreatment on sequentially-extracted phosphorus fractions from peat soils

Abstract

The composition and peculiarity of peat requires a critical evaluation of pretreatment for their effects on sequentially-extracted phosphorus (P) fractions. Therefore, these effects were determined on the sequential P fractionation scheme according to Hedley, which has been seldom applied to peat soils. A field-moist, low-moor peat was sampled and subjected to two drying and three storing techniques prior to the Hedley P fractionation. The P concentrations in nearly all fractions differed among treatments. The proportions of resin-P and NaHCO₃-P decreased in the order fresh>frozen>cool stored. Drying led to great increases in the proportion of residual P, most of which was assigned to organic P forms. Organic P extracted by NaHCO₃ and NaOH disappeared or was lowered in proportion due to drying. It was concluded that sequential P fractionation should be carried out with fresh peat samples to avoid undesired changes in the fractions.

Acknowledgments

This study was financially supported by the European Community in the research project PROWATER (contract number EVK1-CT-1999-00036) of the Fifth Framework Program. We like to thank Mrs. M. Hopp and Mrs. R. Henkel for their technical assistance in the laboratory.