Fig. 4

Solution ³¹P NMR spectra of the undiluted soil extract with a paramagnetic ion concentration of 245 mg L⁻¹ using a recycle delay time of 0.1 and 2 s. Assignments are given for each class of P compounds above their respective peaks. Numbers refer to the percentage of spectral area for each class. The inset shows the expanded regions of phosphonate, orthophosphate monoester and pyrophosphate regions