Extended Data Fig. 4: Time-averaged CO₂ response of all individual phosphorus (P) concentration variables.

(a) CO₂ effect on major vegetation P concentration (%); (b) CO₂ effect on major soil Hedley fractionation P concentrations (%), and (c) CO₂ effect on major soil P concentration (%). The solid dots indicate the mean absolute CO₂ effect, calculated by using elevated minus ambient CO₂ treatment (n = 3), with the coloured bars indicating confidence intervals at 95%, 85% and 75% (two-tailed t-test, with shallower colours indicating higher confidence levels). If the coloured bars intercept with zero, it means that the reported CO₂ effect size is not significantly different from zero at the respective confidence levels. The black bars indicate standard errors of the treatment difference.