Effects of the earthworm Pontoscolex corethrurus on rice P nutrition and plant-available soil P in a tropical Ferralsol /Trap, Jean /Blanchart, Eric Ratsiatosika, O. Razafindrakoto, M. /Becquer, Thierry Andriamananjara, A. Morel, C. Endogeic earthworms P-32-labeling Isotopic dilution L-value Upland rice Madagascar 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. 2021 text https://www.documentation.ird.fr/hor/fdi:010081032 fdi:010081032 Trap Jean, Blanchart Eric, Ratsiatosika O., Razafindrakoto M., Becquer Thierry, Andriamananjara A., Morel C.. Effects of the earthworm Pontoscolex corethrurus on rice P nutrition and plant-available soil P in a tropical Ferralsol. 2021, 160, 103867 [5 ] EN MADAGASCAR ZONE TROPICALE