The Nature of Alkali‐soluble Soil Organic Phosphates

Summary Fractionation of the phosphates in a sodium hydroxide extract of an arable soil has shown the presence of a number of esters of a type not previously detected in soils. These included several mono‐phosphorylated carboxylic acids with C to P ratios of approximately 7 or 8 to I and two esters each containing glycerol, myoinositol, chiroinositol and an unidentified component. Another ester, probably containing two phosphate groups, was also detected but was not completely separated from other compounds containing no P. These esters constituted only approximately 3 per cent of the total soil organic P but considerable losses of organic P occurred during the extraction and isolation procedures. The amounts of the inositol phosphates, nucleoside phosphates, and inorganic pyrophosphate in the extract were also measured.