The inositol phosphates in soils and manures: Abundance, cycling, and measurement

Abstract

Giles, C. D., Cade-Menun, B. J. and Hill, J. E. 2011. The inositol phosphates in soils and manures: Abundance, cycling, and measurement. Can. J. Soil Sci. 91: 397–416. This review focuses on recent advances in understanding the origins, abiotic and biotic cycling, and measurement of inositol phosphates (IPx) in manures and soils. With up to eight orthophosphates bound to inositol via ester linkages, this class of compounds has the potential to be unavailable to enzymatic hydrolysis when sorbed or in complex with soil metals, limiting the release of phosphorus (P) for uptake by plants. However, hydrolysis of IPx by microbial phytases in aquatic environments could result in a potent source of the eutrophication agent orthophosphate. This review discusses the forms and stereoisomers of IPx that have been identified in environmental samples. Next, it discusses the various techniques used to identify IPx, including extraction and concentration, separation techniques such as electrophoresis, spectroscopic methods such as phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR), mass spectrometry and X-ray absorption near-edge structure (XANES), and enzymatic techniques, such as enzyme hydrolysis (EH). Recent advances in knowledge about abiotic and biotic factors controlling the cycling of IPx in soil, manure and water are summarised, including soil characteristics affecting IPx sorption, transportation processes, and the microbial production and degradation of IPx. Finally, areas for future research focus are discussed.