5. Conclusions
We show that the method of inoculation can strongly influence
the soil effect on plant performance. The strongest negative soil
effect was observed when using sieved field soil. By sieving the soil
to obtain a microbial suspension the negative soil effect was
reduced, and this was observed during both growth phases. In
addition, we show that the results obtained with inoculating sieved
field soil or with an aqueous soil suspension are not comparable in
terms of effect strength. Thus, when designing plantesoil feedback
experiments, it is crucial to consider that soil inoculum preparation
can strongly influence the effect size.