Lopez-Hernandez D. auteur aut IRD Brossard Michel auteur aut IRD Frossard E. auteur aut IRD text journalArticle eng text/pdf reformatted digital access The productivity of many agricultural systems is determined by the quantity of inorganic P (Pi) made available through mineralisation of organic P (Po) during the growing season. Because of the adsortive nature of the soil mineral fraction, any recently-mineralised Po may be rapidly partitioned to the solid phase. Attempts to quantify Po mineralisation, have been unsuccessful due to the difficulties in separating recently-released Pi from labile Pi forms already existing in the soil. We have investigated the use of an isotopic dilution technique to measure the increase of isotopically-exchangeable P with time (E(t)) in : a short-term experiment (1-100 min) where there was only the physico-chemical process of exchange of solution 32P with 31P located on the solid phase ; and an incubation experiment (0-51 d) where there were both physico-chemical and biological (immobilisation and mineralisation) processes. Although the E(t) values were obtained by different means (water- and resin-Pi extractions), the marked difference between both values during the 51 d experiment could not be completely explained by 32P exchange with 31P in the solid phase. The strong association between E(t) increment with Po and CO2 respiration values during incubation suggest biological participation. Estimates of Po mineralisation and CO2 respiration values during incubation suggest biological participation. Estimates of Po mineralisation rates for the low P-sorbing soils (220-900 microg P/kg/d) were similar to values in the literature that were obtained by isotopic and non-isotopic methods. (Résumé d'auteur) specialized FERTILITE DU SOL PHOSPHORE ORGANIQUE MINERALISATION MESURE ISOTOPE 068PEDAPP 30 13 1663-1670 1998 0038-0717 https://www.documentation.ird.fr/hor/fdi:010014889 10.1016/S0038-0717(97)00255-1 0038-0717 [F B010014889] https://www.documentation.ird.fr/hor/fdi:010014889 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_51-52/010014889.pdf IRD - Base Horizon / Pleins textes 1998-09-17 2018-06-15 fdi:010014889 fre