Soil inoculum identity and rate jointly steer microbiomes and plant communities in the field

Abstract

Inoculation with soil from distinctly different ecosystems has been reported to induce directional changes in the plant and soil communities, however, a major question is how specific these inoculations are and whether different inocula collected from a similar ecosystem will also lead to differential ecosystem development at the recipient site. We conducted a soil inoculation field experiment at a degraded grassland with two different soil inocula both from grasslands and used three inoculation depths. We then measured the development of plant and soil communities over a period of three years following soil inoculation. Our results show that soil and plant communities diverged and that these effects were stronger with increasing inoculation amount. Inoculation with upland meadow soil at the recipient site resulted in more complex biotic networks than inoculation with meadow steppe soil. Our experiment highlights that soil inoculation can promote restoration of degraded ecosystems but that the direction and speed of ecosystem development depend on the origin of the inoculum and the amount of inoculum used.