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Phosphorus composition of upland soils polluted by long-term atmospheric nitrogen deposition

Turner, BL; Chudek, JA; Whitton, BA; Baxter, R


BL Turner

JA Chudek

BA Whitton


Atmospheric N deposition can enhance biological P limitation in terrestrial ecosystems and increase the importance of organic P to plants and microorganisms. We used NaOH–EDTA extraction and solution 31P NMR spectroscopy to determine the P composition of soils in the Upper Teesdale National Nature Reserve, northern England, an upland region influenced by such deposition for at least 150 years. Three characteristic soil types were sampled on three occasions during an annual cycle: blanket peat (318 mg g–1 total C, 607 g g–1 total P, pH 3.9); acid organic soil under grassland (354 mg g–1 total C, 1190 g g–1 total P, pH 3.7); calcareous soil under grassland (140 mg g–1 total C, 649 g g–1 total P, pH 7.3). Between 58 and 99% of the total P in soil and litter layers was extracted by 0.25 M NaOH + 0.05 M EDTA. Extracts of all soils were dominated by organic P, mainly in the form of orthophosphate monoesters (43–69% extracted P). The two acidic soils also contained large proportions of orthophosphate diesters (6–19% extracted P) and phosphonates (7–16% extracted P), suggesting that these compounds become stabilised at low pH. However, a seasonal trend of increasing orthophosphate monoester-to-diester ratios, most evident in the calcareous grassland soil, indicated the preferential degradation of orthophosphate diesters during the growing season. Orthophosphate was the major inorganic P compound (17–34% extracted P), and all soils contained pyrophosphate (1–5% extracted P). However, orthophosphate determined in the NaOH–EDTA extracts by solution 31P NMR spectroscopy was substantially greater than that determined by molybdate colourimetry, suggesting that orthophosphate occurred in complexes with humic compounds that were not detected by conventional procedures. Our results suggest that organisms able to use recalcitrant soil organic P may have a competitive advantage in environments under enhanced atmospheric N deposition.


Turner, B., Chudek, J., Whitton, B., & Baxter, R. (2003). Phosphorus composition of upland soils polluted by long-term atmospheric nitrogen deposition. Biogeochemistry, 65(2), 259-274.

Journal Article Type Article
Publication Date Sep 1, 2003
Deposit Date May 21, 2007
Journal Biogeochemistry
Print ISSN 0168-2563
Electronic ISSN 1573-515X
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 65
Issue 2
Pages 259-274
Keywords Nitrogen deposition, Phosphorus, Soil, Upland.