Assessing the ability of soil tests to estimate labile phosphorus in agricultural soils: Evidence from isotopic exchangeVisa övriga samt affilieringar
2019 (Engelska)Ingår i: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 337, s. 350-358Artikel i tidskrift (Refereegranskat) Published
Abstract [en]
Efficient phosphorus (P) fertilization strategies are essential for intensive crop production with minimal negative environmental impacts. A key factor in sustainable P use is assessment of the plant available soil P pool using soil P tests. This study determined isotopically exchangeable P after six days of reaction with 33PO4 (P-E (6 d)) to determine how accurately two commonly used P tests, Olsen and AL (acid ammonium acetate lactate) can quantify the amount of labile P. Soil samples were taken from both highly P-amended and unamended plots at six sites within the Swedish long-term soil fertility experiments. According to P K-edge XANES spectroscopy, the P speciation was dominated by Al-bound P and organic P, with additional contributions from Fe-bound P and Ca phosphates in most soils. The results showed that the AL test overestimated P-E (6 d) by a factor of 1.70 on average. In contrast, the Olsen test underestimated P-E (6 d), with the mean ratios of P-Olsen to P-E (6 d) being 0.52 for high-P and 0.19 for low-P soils. The 33P/31P ratio in the Olsen extract of a 33PO4 spiked soil was closer to that of a 0.005 mol L−1 CaCl2 soil extract than the corresponding ratio in the AL extract, suggesting that AL extraction solubilized more non-labile P. In conclusion, the AL and Olsen methods are not suitable for direct quantification of the isotopically exchangeable soil P pool after 6 days of equilibration. However, based on the results, Olsen may be superior to AL for classification of soil P status, due to its even performance for calcareous and non-calcareous soils and lower extraction of non-labile P.
Ort, förlag, år, upplaga, sidor
Elsevier, 2019. Vol. 337, s. 350-358
Nyckelord [en]
Chemical analysis, Isotopes P-33, Isotopic exchange kinetic technique, Phosphorus, Soil P test, Soils, Chlorine compounds, Cultivation, Environmental impact, Extraction, Isotopes, Soil testing, X ray absorption near edge structure spectroscopy, Agricultural soils, Ammonium acetate, Crop production, IS assessment, Isotopic exchange, Isotopic exchange kinetics, Noncalcareous soils, Soil fertility
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Annan lantbruksvetenskap
Forskningsämne
Mark- och vattenteknik
Identifikatorer
URN: urn:nbn:se:kth:diva-236319DOI: 10.1016/j.geoderma.2018.09.048ISI: 000456761500036Scopus ID: 2-s2.0-85054011888OAI: oai:DiVA.org:kth-236319DiVA, id: diva2:1264361
Anmärkning
QC 20181120
2018-11-202018-11-202022-06-26Bibliografiskt granskad