Content of Inositol Penta‐ and Hexaphosphates in Some Canadian Soils

Summary The combined amounts of inositol penta‐ and hexaphosphates in a number of Canadian soils of differing origin have been measured. The esters were precipitated as barium salts from alkali extracts and purified by anion‐exchange chromatography; their identity was confirmed by paper‐partition chromatography. An alternative method involving precipitation of the esters as ferric salts in acid medium was found to give much lower values, probably because of incomplete precipitation. Values for eighteen surface soils ranged from 20 to 71 and for twelve subsoils from 18 to 43 ppm P. The amounts found were related to the contents of both total phosphate and total organic phosphate, and accounted, on average, for 6 per cent of the former and 17 per cent of the latter. A correlation of +0.67 (P < 0.01) was found with orthophosphate retention capacity but correlations with soil N and C contents were poor. Amounts of the esters were higher in forest soils than in grassland soils.