Table 1.

Correlation coefficients (Pearson r) and p-value (in brackets) between soil pH, soil total C, Soil C:N ratio and mean annual precipitation (MAP) and the response ratios of total root biomass, coarse root biomass and fine root biomass. Bold number indicates significant p-values at 0.05. The sign indicates the direction of the slope. Aridity was calculated as [AI in this dataset – AI in each site] so increases in aridity represent places with low water availability.

	Total Root Biomass (ln RR)	Coarse Root Biomass (ln RR)	Fine Root Biomass (ln RR)
Soil pH	0.01 (0.67)	(−) 0.25 (0.11)	(−) 0.27 (0.09)
Soil Total C	0.07 (0.69)	(−) 0.19 (0.44)	0.334 (0.04)
Soil C:N	0.16 (0.35)	(−) 0.59 (0.65)	(−) 0.35 (0.03)
MAP	0.27 (0.10)	0.29 (0.33)	(−) 0.32 (0.04)