hydrolyzable phosphorus

Phosphorus in the sample as measured by the sulfuric acid hydrolysis procedure, and minus pre-determined orthophosphates (EPA, 1979). Includes dissolved and particulate condensed phosphate that is converted to dissolved orthophosphate through acidification of the sample (APHA, 1989). It is referred to as Dissolved hydrolyzable P or Total hydrolyzable P, when measured on filtered or  unfiltered sample, respectively.