Fig. 2. Consistent occurrence of significant P limitation in all types of ecosystems.

a Significant P limitation occurred in the natural terrestrial ecosystems at almost all latitudes. The magnitude of P limitation decreased with latitude in wetlands (meta-regression, R² = 0.35, P < 0.05, N = 85) but not in any other type of natural terrestrial ecosystem (meta-regression, P > 0.05). b Significant P limitation occurred in all types of natural terrestrial ecosystems. Values in the brackets indicate the percentage of significant P limitation cases in the total sample size in each type of natural terrestrial ecosystem. c Significant P limitation occurred in croplands at all explored latitudes (absolute latitude between 0.1^° and 56.5^°), and the magnitude of P limitation decreased with absolute latitude (meta-regression, R² = 0.16, P < 0.05, N = 216). d Significant P limitation was found in 48.6% of the P-fertilization experiments in the croplands. As in Fig. 1, statistical significance of P limitation was assessed based on the Ln(Response Ratio). Dashed lines in all plots (0.23 in (a) and (b), 0.09 in (c) and (d)) indicate where the magnitude of P limitation approximates a 0.05 significance level (Z test). In (a) and (c), the size of each point is proportional to the weight used for meta-regression analysis. Source data are provided as a Source Data file.