Data from: Relative importance of competition and plant-soil feedback, their synergy, context dependency and implications for coexistence

Plants interact simultaneously with each other and with soil biota, yet
the relative importance of competition versus plant soil feedback (PSF) on
plant performance is poorly understood. Using a meta-analysis of 38
published studies and 150 plant species, we show that effects of
interspecific competition (either growing plants with a competitor or
singly, or comparing inter- vs. intraspecific competition) and PSF
(comparing home vs. away soil, live vs. sterile soil, or control vs.
fungicide-treated soil) depended on treatments but were predominantly
negative, broadly comparable in magnitude, and additive or synergistic.
Stronger competitors experienced more negative PSF than weaker competitors
when controlling for density (inter- to intraspecific competition),
suggesting that PSF could prevent competitive dominance and promote
coexistence. When competition was measured against plants growing singly,
the strength of competition overwhelmed PSF, indicating that the relative
importance of PSF may depend not only on neighbor identity but also
density. We evaluate how competition and PSFs might interact across
resource gradients; PSF will likely strengthen competitive interactions in
high resource environments and enhance facilitative interactions in low
resource environments. Finally, we provide a framework for filling key
knowledge gaps and advancing our understanding of how these biotic
interactions influence community structure.