Fig. 2: Soil pH, N2O EF, N fertilization rate in tropical, subtropical and temperate regions, and tea plantations.
From: Intermediate soil acidification induces highest nitrous oxide emissions
Average soil pH (a), N2O emission factors (EFs) (b), N fertilization rates (c) in different climate zones, and relationship between N2O EFs and soil pH (d) or N fertilization rates (e) in tea plantations. In a–c bars represent mean ± s.e.m and the sample size ‘n’ represents independent samples. In a–c different letters indicate a statistical significance of the effect based on non-parametric Wilcoxon test (P < 0.05) using the Benjamini and Hochberg (BH) method. The error bands (shaded areas) in (d and e) represent the 95% confidence intervals around best-fit regression line. Statistics (adjusted R2 and P values) for linear regression are indicated. The exact P values: P < 0.001 in (a, c), and P = 0.027 in (b). Source data are provided as a Source Data file.
