title: Characterization of leached phosphorus from soil, manure, and manure-amended soil by physical and chemical fractionation and Diffusive Gradients in Thin films (DGT).
abstract: We are challenged to date to fully understand mechanisms controlling phosphorus (P) mobilization in soil. In this study we evaluated physical properties, chemical reactivity, and potential bioavailability of P mobilized in soil during a leaching event and examined how the amounts and properties of leached P were influenced by surface application of cattle manure. Leaching experiments on manure itself, and on intact soil columns (14.1 cm inner dia., 25 cm height) before and after manure application, were carried out at an irrigation rate of 1 mm h(-1) for 48 h. High concentrations of dissolved reactive P (DRP) were found in manure leachates (up to 32 mg L(-1)), whereas concentrations of P in soil leachates were low both before and after manure application (around 0.04 mg L(-1) before application and up to 0.4 mg L(-1) afterward). This result indicates that the soil retained most of the P added with manure. Manure particles themselves were also largely retained by the soil. Combined physical (centrifugation) and chemical (molybdate reactiveness) fractionation of leached P showed that leachates in the manure treated soils were dominated by dissolved unreactive P (DUP), mainly originating from manure. However, centrifugation only removed a small fraction of total particles from the leachates, indicating that the so-called dissolved fraction may be associated with low density particulate matter. Deployment of Diffusive Gradients in Thin films (DGT) devices in the leachates proved to be a good approach for measuring reactive P in soil leachates. The results indicated that total reactive P (TRP) gave a better estimate of potentially bioavailable P than both total P (TP) and DRP in these experiments.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, Mawson Lakes Campus, University of South Australia, Mawson Lakes, South Australia 5095, Australia. nadia.glaesner@gmail.com
authors.forename: Nadia
authors.initials: N
authors.lastname: Glæsner
authors.forename: Erica
authors.initials: E
authors.lastname: Donner
authors.forename: Jakob
authors.initials: J
authors.lastname: Magid
authors.forename: Gitte H
authors.initials: GH
authors.lastname: Rubæk
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Enzo
authors.initials: E
authors.lastname: Lombi
mesh_terms: D057914:Agricultural Irrigation; D000818:Animals; D001682:Biological Availability; D002417:Cattle; D002498:Centrifugation; D005591:Chemical Fractionation; D005308:Fertilizers; D008372:Manure; D052638:Particulate Matter; D010758:Phosphorus / Q000032:analysis* / Q000737:chemistry* / Q000493:pharmacokinetics; D012987:Soil
chemical_list: D005308:Fertilizers; D008372:Manure; D052638:Particulate Matter; D012987:Soil; D010758:Phosphorus