Richness of rhizosphere organisms affects plant P nutrition according to P source and mobility /Trap, Jean Ranoarisoa, P. M. Irshad, U. Plassard, C. soil P status rhizospheric organisms bacteria nematodes mycorrhizal fungi biodiversity-function relationships Plants evolve complex interactions with diverse soil mutualist organisms to enhance P mobilization from the soil. These strategies are particularly important when P is poorly available. It is still unclear how the soil P source (e.g., mineral P versus recalcitrant organic P) and its mobility in the soil (high or low) affect soil mutualist biological (ectomycorrhizal fungi, bacteria and bacterial-feeding nematodes) richness-plant P acquisition relationships. Using a set of six microcosm experiments conducted in growth chamber across contrasting P situations, we tested the hypothesis that the relationship between the increasing addition of soil mutualist organisms in the rhizosphere of the plant and plant P acquisition depends on P source and mobility. The highest correlation (R-2 = 0.70) between plant P acquisition with soil rhizosphere biological richness was found in a high P-sorbing soil amended with an organic P source. In the five other situations, the relationships became significant either in soil conditions, with or without mineral P addition, or when the P source was supplied as organic P in the absence of soil, although with a low correlation coefficient (0.09 < R-2 < 0.15). We thus encourage the systematic and careful consideration of the form and mobility of P in the experimental trials that aim to assess the role of biological complexity on plant P nutrition. 2021 text https://www.documentation.ird.fr/hor/fdi:010080985 fdi:010080985 Trap Jean, Ranoarisoa P. M., Irshad U., Plassard C.. Richness of rhizosphere organisms affects plant P nutrition according to P source and mobility. 2021, 11 (2), 157 [9 ] EN