Characterisation of water-extractable soil organic phosphorus by phosphatase hydrolysis

Abstract

Information on the chemical forms of organic phosphorus (P) in soil waters is fundamental to understanding the dynamics of soil organic P and its potential for transfer from soils to watercourses. Phosphatase enzymes were used to classify water-extractable molybdate-unreactive P (MUP) from five Australian pasture soils into compounds that could be hydrolysed by (i) alkaline phosphomonoesterase (comprising labile orthophosphate monoesters, such as sugar phosphates), (ii) a combination of phosphodiesterase and alkaline phosphomonoesterase (comprising labile orthophosphate monoesters and orthophosphate diesters, such as nucleic acids and phospholipids), and (iii) phytase (including inositol hex..