Extended Data Fig. 1: Effects of elevated CO2 levels on crop yield and grain N content in global croplands.
From: Nitrogen cycles in global croplands altered by elevated CO2
Effects of elevated CO2 levels on (a) crop yield and (b) grain N content by crop groups; (c) crop yield by manipulation methods, including FACE (Free-air CO2 Enrichment Experiment), OTC (Open-top Chamber), and GC (Growth Chamber); (d) BNF by climate zones. The error bars indicate the 95% confidence interval of the mean, which is significant if the 95% confidence interval does not overlap zero. Numbers in the parentheses denote the number of observations in the meta-analysis.
