Use of p-nitrophenyl phosphate for assay of soil phosphatase activity

A simple method of assaying soil phosphatase activity is described. It involves colorimetric estimation of the p-nitrophenol released by phosphatase activity when soil is incubated with buffered (pH 6·5) sodium p-nitrophenyl phosphate solution and toluene at 37° C for 1 hr. The method is rapid and precise, and it has significant advantages over methods previously proposed for assay of soil phosphatase activity.