Characterizing phosphorus in environmental and agricultural samples by 31P nuclear magnetic resonance spectroscopy

Phosphorus nuclear magnetic resonance (31P-NMR) spectroscopy has advanced our knowledge of organic phosphorus (P) in soils and environmental samples more than any other technique. This paper reviews the use of 31P-NMR spectroscopy for soil, water and other environmental samples. The requirements for a successful solid-state or solution 31P-NMR experiment are described, including experimental set-up, sample preparation, extractants, experimental conditions, and post-experimental processing. Next, the literature on solid-state and solution 31P-NMR spectroscopy in environmental samples is reviewed, including papers on: methods; P transformations; agricultural, forest and natural ecosystem soil studies; humic acid and particle size separations; manure, compost and sludge studies; and water research, including freshwater, estuary and marine studies. Future research needs are also discussed as well as suggestions to improve results, such as increased standardization among research groups.