Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Applied Soil Ecology 103867 [5 ] Endogeic earthworms P-32-labeling Isotopic dilution L-value Upland rice Madagascar MADAGASCAR ZONE TROPICALE 2021 fdi:010081032 ENG Applied Soil Ecology 0929-1393 ISI:000618081000008 10.1016/j.apsoil.2020.103867 https://www.documentation.ird.fr/hor/fdi:010081032 https://www.documentation.ird.fr/intranet/publi/2021/03/010081032.pdf 160 Horizon (IRD) We conducted a greenhouse experiment in mesocosms for 28 days to assess the effects of the endogeic earthworm Pontoscolex corethrurus on plant-available soil phosphorus (P) and rice (Oryza sativa) P nutrition in a Malagasy Ferralsol. To assess plant-available soil P, we determined the L-value by measuring the specific activity of P taken up from the soil by rice and by applying the isotopic dilution principle. Despite earthworm mortality, P. corethrurus significantly increased rice shoot biomass (+26%) and P nutrition (+65%), confirming that the soil used for the experiment was P-deficient. The L-value also markedly increased from 6.8 +/- 0.9 to 14.2 +/- 1.3 mg P mesocosm(-1) in the presence of P. corethrurus. We estimated that the orthophosphate ions released due to earthworm mortality contributed to 30% of the L-value increase. We attributed the remaining 70% increase to the solubilization of native soil P during its transit through the digestive tract. Thereafter, we discussed the sources of uncertainty associated with the L-value calculation and their utilization to assess earthworm effects on P availability in further studies. 076 ; 074 UR210 Madagascar