Table 1

Extraction of Inorganic P from Soils*

Extractant
P forms extracted

NaOH/NaCl
Al- and Fe-bound
Na citrate-bicarbonate (CB)
Labile pedogenic Ca-rich
Na citrate (C)
Pedogenic Ca-phosphates
Na citrate-ascorbate (CA)
Occluded in poorly crystalline Fe-oxides
Na citrate-bicarbonate-dithionite (CBD)
Occluded in crystalline Fe-oxides
Na acetate
Ca phosphates (excl. lithogenic apatite)
HCl
Lithogenic apatite

*adapted from ref. [23]

von Wandruszka Geochemical Transactions 2006 7:6   doi:10.1186/1467-4866-7-6