Phosphorus speciation of clay fractions from long-term fertility experiments in Sweden
2015 (English)In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 241, 68-74 p.Article in journal (Refereed) Published
Phosphorus (P) losses from agricultural soils constitute a main driver for eutrophication of the Baltic Sea. There is limited knowledge about sorption and release processes of P in these soils, especially concerning the effects of fertilization. In this study, P speciation of the clay fractions from six different soils in long-term fertility experiments in Sweden was investigated by P K-edge XANES spectroscopy. As expected, unfertilized soils had lower concentrations of acid-digestible P compared with fertilized soils. Based on best-fit standards that emerged from linear combination fitting (LCF) of XANES spectra, phosphate sorbed on iron (Fe) (hydr)oxides was a dominant P species in clay fractions from unfertilized soils containing more than 35 mmol kg(-1) of oxalate-extractable Fe. In contrast, P sorbed on aluminum (Al) (hydr)oxides predominated in soils with lower concentrations of oxalate-extractable Fe. A greater proportion of organically bound P was fit for soil samples containing >2% organic carbon. The soils included one calcareous soil for which a greater proportion of P was fit as apatite. After long-term fertilization, P had accumulated mainly as P adsorbed to Al (hydr) oxides according to the XANES analysis. Our research shows that P speciation in fertilized agricultural soils depended on the level of P buildup and on the soil properties.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 241, 68-74 p.
Soils, X-ray absorption spectroscopy, Sweden, Phosphorus, Phosphate, Clays
IdentifiersURN: urn:nbn:se:kth:diva-160733DOI: 10.1016/j.geoderma.2014.10.023ISI: 000348083700008ScopusID: 2-s2.0-84919934924OAI: oai:DiVA.org:kth-160733DiVA: diva2:792102
FunderSwedish Research Council Formas, 2010-1677
QC 201503032015-03-032015-02-272016-03-01Bibliographically approved