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).

Bivariate relationships were significant (P0.05) 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.