Soil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect on F. rubra, root foraging by D. deltoides decreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D. deltoides arose via either a root growth‐dependent pathway (forb metabolome) or a root trait‐dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants.

Priority effects can have long-lasting consequences for the structure and functioning of plant communities. Currently, it is poorly understood to what extent the rhizo-sphere metabolome of plant communities is conditioned by its species composition and whether these changes affect subsequent species during assembly. We collected soil solutions from plant communities differing in species and functional group composition (forbs or grasses). We evaluated the effect of the rhizosphere metabolome found in the soil solutions on the growth, biomass allocation, and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). The rhizosphere metabolome of forb and grass communities differed in composition and chemical diversity. While F. rubra did not respond to different rhizosphere solutions, soil exploration by D. deltoides roots decreased when plants received the rhizosphere solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration by D. deltoides arose via either a root growth-dependent pathway (forb metabolome) or a root trait-dependent pathway (grass metabolome). Reduced soil exploration was not connected to a decrease in total N uptake. Our findings reveal that rhizosphere chemical cues can affect later arriving plants and create belowground priority effects in grasslands.