Figure 2: Soil N isotopes and edaphic characteristics.
From: Aridity threshold in controlling ecosystem nitrogen cycling in arid and semi-arid grasslands
Soil δ15N (a), total nitrogen concentration (Soil N, b), soil C/N ratio (c) and pH (d) of study sites along an AI gradient. A second-order polynomial fit well described the relationship between AI and soil δ15N (R2=0.76) and the maximum of this curve was at AI=0.32. Soil N concentration, C/N ratio and pH showed different patterns with increasing AI above and below the threshold AI=0.32.
