Table 1. Summary of SMA regressions of log₁₀-transformed C, N, and P contents in soil and microbial pools, along with predictors of soil C mineralization (CO₂) and microbial metabolism (qCO₂).

Analysis	x	y	n	r2	Int.	Slope	x∶y ratio	x∶y mean			CV
Soil allometry	*C	N	280	0.86	−0.77	0.88	C∶N	18.8	±	0.8	0.7
	*C	P	261	0.18	0.23	0.29	C∶P	445	±	43	1.6
	*N	P	261	0.24	0.27	0.42	N∶P	21.4	±	1.7	1.3
Microbial allometry	MBC	MBN	237	0.84	−1.11	1.08	mC∶N	10.7	±	0.6	0.8
	*MBC	MBP	298	0.70	−2.07	1.18	mC∶P	87.2	±	13.2	2.6
	MBN	MBP	267	0.71	−0.79	1.04	mN∶P	9	±	1.2	2.2
Microbial biomass	C	MBC	289	0.75	−1.34	0.88	MBC∶C	2.01%	±	0.08	0.6
	N	MBC	266	0.73	−0.52	0.99
	*P	MBC	247	0.132	0.08	1.37
Respiration and metabolism	MBC	CO2	92	0.7	−4.17	1.57
	**mC∶P	qCO2	92	0.21	1.97	−1.15
	**Pi	qCO2	38	0.44	0.51	0.65

Bivariate relationships were significant (P<0.001) for all relationships shown. Slopes significantly different from one (P>0.05) are shown in boldface font. Slopes not different from one (not bold) indicate an isometric (linear) relationship among parameters. The geometric mean and standard errors (SE) of stoichiometric ratios (x∶y ratio, x∶y mean) are given for reference, but are not representative where allometric slopes are different than 1. The coefficient of variation (CV) of these stoichiometric ratios is provided as a dimensionless index of dispersion about the mean. Single asterisks (*) indicate where different slopes are observed by considering only forest and pasture soils (Table S1), and ** indicates relationships fit for all soils excluding litter and humus.