Fig. 1. Phosphorus-31 nuclear magnetic resonance (NMR) spectra of manure and lagoon samples extracted with 0.5 M NaOH + 0.1 M Na₂EDTA. The NMR parameters were 202.45 MHz, 90° pulse, 0.68-s acquisition, 4.32-s delay, 25°C, 8000 scans, and 20-Hz line broadening. The * marks the diagnostic peak for phytic acid, and the insets show expanded orthophosphate monoester and diester regions (off-set for the manure sample), and an expanded phosphonate region for the manure sample.