Linking phosphorus sequestration to carbon humification in wetland soils by P-31 and C-13 NMR spectroscopy

Hamdan, Rasha, El-Rifai, Hasan M., Cheesman, Alexander W., Turner, Benjamin L., Reddy, K. Ramesh, and Cooper, William T. (2012) Linking phosphorus sequestration to carbon humification in wetland soils by P-31 and C-13 NMR spectroscopy. Environmental Science and Technology, 46 (9). pp. 4775-4782.

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Abstract

Phosphorus sequestration in wetland soils is a prerequisite for long-term maintenance of water quality in downstream aquatic systems, but can be compromised if phosphorus is released following changes in nutrient status or hydrological regimen. The association of phosphorus with relatively refractory natural organic matter (e.g., humic substances) might protect soil phosphorus from such changes. Here we used hydrofluoric acid (HF) pretreatment to remove phosphorus associated with metals or anionic sorption sites, allowing us to isolate a pool of phosphorus associated with the soil organic fraction. Solution P-31 and solid state C-13 NMR spectra for wetland soils were acquired before and after hydrofluoric acid pretreatment to assess quantitatively and qualitatively the changes in phosphorus and carbon functional groups. Organic phosphorus was largely unaffected by HF treatment in soils dominated by refractory alkyl and aromatic carbon groups, indicating association of organic phosphorus with stable, humified soil organic matter. Conversely, a considerable decrease in organic phosphorus following HF pretreatment was detected in soils where O-alkyl groups represented the major fraction of the soil carbon. These correlations suggest that HF treatment can be used as a method to distinguish phosphorus fractions that are bound to the inorganic soil components from those fractions that are stabilized by incorporation into soil organic matter.

Item ID: 35624
Item Type: Article (Research - C1)
ISSN: 1520-5851
Funders: U.S. Department of Agriculture
Projects and Grants: U.S. Department of Agriculture CSREES 2004-35107-14918
Date Deposited: 01 Oct 2014 15:54
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050102 Ecosystem Function @ 50%
05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050304 Soil Chemistry (excl Carbon Sequestration Science) @ 50%
SEO Codes: 96 ENVIRONMENT > 9614 Soils > 961499 Soils not elsewhere classified @ 100%
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