Fig. 1

Potential relationships between management and rhizosphere effects. Conceptual framework of scenarios for management (M) and rhizosphere (R) effects on microbiomes. a M effects could be stronger than R, leading to stronger differences between microbial communities in different systems than between bulk soil and rhizosphere communities. b Conversely, R effects could be stronger than M, leading to distinct bulk and rhizosphere communities across management systems. c If M and R effects are additive, plant effects act consistently on distinct bulk soil pools. Rhizosphere communities thus differ from bulk soil and differ from one another by the same amount as their respective bulk soil communities do. d An M × R interaction is present, and the magnitude or direction of the rhizosphere effect could differ between systems. In addition, differences between rhizosphere communities could be greater than differences between bulk soil communities