title: A method for analyzing the δ18O of resin-extractable soil inorganic phosphate.
abstract: Improved tools for tracing phosphate transformations in soils are much needed, and can lead to a better understanding of the terrestrial phosphorus cycle. The oxygen stable isotopes in soil phosphate are still not exploited in this regard. Here we present a method for measuring the oxygen stable isotopes in a fraction of the soil phosphate which is rapidly available to plants, the resin-extractable P. This method is based on extracting available phosphate from the soil with anion-exchange membranes, soil organic matter removal by a resin, purification by precipitation as cerium phosphate, and finally precipitation as silver phosphate. The purified silver phosphate samples are then measured by a high-temperature elemental analyzer (HT-EA) coupled in continuous flow mode to an isotope ratio mass spectrometer. Testing the method with Mediterranean and semi-arid soils showed no artifacts, as well as good reproducibility in the same order as that of the HT-EA analytical uncertainty (0.3‰).
authors.affiliation: The Institute of Earth Sciences, The Hebrew University of Jerusalem, Israel.
authors.forename: Tal
authors.initials: T
authors.lastname: Weiner
authors.forename: Shunit
authors.initials: S
authors.lastname: Mazeh
authors.forename: Federica
authors.initials: F
authors.lastname: Tamburini
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Frossard
authors.forename: Stefano M
authors.initials: SM
authors.lastname: Bernasconi
authors.forename: Tommaso
authors.initials: T
authors.lastname: Chiti
authors.forename: Alon
authors.initials: A
authors.lastname: Angert