Fig. 4. The impacts of cumulative nitrogen addition on overyielding.

The impacts of cumulative N addition on net biodiversity effects (a, d, g), complementarity effects (b, e, h) and selection effects (c, f, i). Cumulative N addition includes inputs from experimental addition (a–c), atmospheric deposition (d–f) and both (g–i). Black lines indicate fixed effect, colored lines indicate random effect. The x-axes are on the log scale with unit kg/ha, the y-axes are on the original scale with unit g/m²/year.