Aims: Plant-soil interactions are important drivers of plant productivity and community structure. Biocrusts – soil surface-dwelling biotic communities comprised of cyanobacteria, fungi, bryophytes, and/or lichens - are widespread in drylands globally. Biocrusts are described as “mantles of fertility” and have been shown to have facilitative, but species-specific effects on plant productivity. Yet, patterns and mechanisms underlying biocrust facilitation of plant productivity remain unclear. Methods: Using mesocosms with bare soil versus biocrust cover we investigated the effects of biocrusts on plant biomass allocation, leaf chemistry and colonization by root-associated fungi. Results: Plant responses to biocrust presence were species-specific. Overall, biocrusts were associated with increased plant biomass and/or leaf N concentrations in Elymus elymoides, Bouteloua gracilis and Zea mays. However, plants grown in biocrusts had lower root-associated fungal colonization compared to bare soils. Conclusions: Biocrusts were associated with increased plant biomass and leaf N. Yet, plant growth responses to biocrusts were not correlated with differences in root-associated fungal colonization between soil mesocosm types. Understanding species-specificity in biocrust facilitation of plant growth may have important implications for understanding plant community structure in dryland ecosystems.