title: Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils.
abstract: We have used an integrated approach to study the mobility of inorganic phosphorus (P) from soil solid phase as well as the microbial biomass P and respiration at increasing doses of citric and oxalic acid in two different soils with contrasting agronomic P status. Citric or oxalic acids significantly increased soil solution P concentrations for doses over 2 mmol kg-1. However, low organic acid doses (<2 mmol kg-1) were associated with a steep increase in microbial biomass P, which was not seen for higher doses. In both soils, treatment with the tribasic citric acid led to a greater increase in soil solution P than the dibasic oxalic acid, likely due to the rapid degrading of oxalic acids in soils. After equilibration of soils with citric or oxalic acids, the adsorbed-to-solution distribution coefficient (Kd) and desorption rate constants (k-1) decreased whereas an increase in the response time of solution P equilibration (Tc) was observed. The extent of this effect was shown to be both soil and organic acid specific. Our results illustrate the critical thresholds of organic acid concentration necessary to mobilize sorbed and precipitated P, bringing new insight on how the exudation of organic acids regulate chemical-microbial soil phosphorus transformations.
authors.affiliation: Lancaster University, Lancaster Environment Centre , Lancaster, LA1 4YQ, U.K.
authors.forename: Daniel
authors.initials: D
authors.lastname: Menezes-Blackburn
authors.affiliation: Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera , Temuco, Chile.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Paredes
authors.affiliation: Lancaster University, Lancaster Environment Centre , Lancaster, LA1 4YQ, U.K.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Courtney D
authors.initials: CD
authors.lastname: Giles
authors.affiliation: Rothamsted Research, North Wyke, Okehampton, Devon, EX20 2SB, U.K.
authors.forename: Tegan
authors.initials: T
authors.lastname: Darch
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Marc
authors.initials: M
authors.lastname: Stutter
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: George
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Charles
authors.initials: C
authors.lastname: Shand
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: David
authors.initials: D
authors.lastname: Lumsdon
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Patricia
authors.initials: P
authors.lastname: Cooper
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Renate
authors.initials: R
authors.lastname: Wendler
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Lawrie
authors.initials: L
authors.lastname: Brown
authors.affiliation: James Hutton Institute, The James Hutton Institute , Aberdeen, AB15 8QH and Dundee, DD2 5DA, Scotland, U.K.
authors.forename: Martin
authors.initials: M
authors.lastname: Blackwell
authors.affiliation: Lancaster University, Lancaster Environment Centre , Lancaster, LA1 4YQ, U.K.
authors.forename: Catherine
authors.initials: C
authors.lastname: Wearing
authors.affiliation: Lancaster University, Lancaster Environment Centre , Lancaster, LA1 4YQ, U.K.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Haygarth
mesh_terms: D000143:Acids; D009930:Organic Chemicals; D010758:Phosphorus; D012987:Soil; D012989:Soil Pollutants
chemical_list: D000143:Acids; D009930:Organic Chemicals; D012987:Soil; D012989:Soil Pollutants; D010758:Phosphorus