Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils

Menezes-Blackburn, Daniel and Paredes, Cecilia and Zhang, Hao and Giles, Courtney D. and Darch, Tegan and Stutter, Marc and George, Timothy S. and Shand, Charles and Lumsdon, David and Cooper, Patricia and Wendler, Renate and Brown, Lawrie and Blackwell, Martin and Wearing, Catherine and Haygarth, Philip M. (2016) Organic Acids Regulation of Chemical-Microbial Phosphorus Transformations in Soils. Environmental Science and Technology, 50 (21). pp. 11521-11531. ISSN 0013-936X

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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.

Item Type:
Journal Article
Journal or Publication Title:
Environmental Science and Technology
Uncontrolled Keywords:
?? general chemistryenvironmental chemistrychemistry(all) ??
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Deposited On:
13 Jun 2023 10:40
Last Modified:
16 Jul 2024 12:03