The molecular size continuum of soil organic phosphorus and its chemical associations

The chemical nature of most organic P (Porg) in soil remains ‘unresolved’ but is accounted for by a broad signal the phosphomonoester region solution 31P nuclear magnetic resonance (NMR) spectra. molecular size range this NMR and its structure remain unclear. aim study was to elucidate Porg with increasing extracts combining exclusion chromatography (SEC) spectroscopy. Gel-filtration SEC carried out on NaOH-EDTA four soils (range 238–1135 mg Porg/kgsoil) collect fractions sizes < 5, 5–10, 10–20, 20–50, 50–70, > 70 kDa. These were then analysed Organic detected across entire continuum from 5 Concentrations 10 kDa fraction ranged 107 427 P/kgsoil exhibited average three signals prominent 10–20 20–50 fractions, accounting 77 % 74 total phosphomonoesters, respectively. Our demonstrates that are present all investigated comprise components varying peak line width (20 250 Hz). stereoisomers myo- scyllo-inositol hexakisphosphates (IP6) also multiple ranges predominant 5–10 fraction. proportion IP associated large 23 (SD = 39 %) soils. findings suggest stabilisation includes processes phase.