Supporting information:

Table 1S. Relative abundances of different carbon groups (in %), measured by 13C CPMAS NMR, in the different soils

N-alkyl, / carboxyl, / O-alkyl C/ / (Arom+phenol)/
Alkyl / methoxy / o-alkyl / acetal / phenolics / arom / amide, ester / Carbonyl / Alkyl/O-Alkyl / (arom +phenol) / Alkyl/N-alkyl / (alkyl + N-alkyl+O-alkyl + arom+phenol)
ppm / 0-45 / 45-65 / 65-95 / 95-108 / 108-145 / 145-160 / 160-185 / 185-225
SBHO / 31.359 / 16.243 / 30.387 / 6.057 / 7.209 / 2.854 / 3.666 / 2.226 / 1.03 / 3.02 / 1.93 / 10.7
SBPA / 35.209 / 16.265 / 30.198 / 5.934 / 5.794 / 2.301 / 1.834 / 2.464 / 1.17 / 3.73 / 2.16 / 8.5
SBPC / 31.912 / 15.707 / 29.639 / 5.732 / 8.255 / 3.106 / 3.061 / 2.588 / 1.08 / 2.61 / 2.03 / 12.0
SBSJ / 26.924 / 16.478 / 31.703 / 6.043 / 8.118 / 3.218 / 4.126 / 3.39 / 0.85 / 2.80 / 1.63 / 12.3

Table 2S. Correlation matrix for the main parameters calculated.

HS-C / FA-C / HA-C / Deh / BR / β-G / Phos / Pol Ox / Ure / G+ / G- / Fungi / Bact / Sat / Mon / WS-P / pH / WS-C / C org / C/N
HS-C
FA-C / 0.90
HA-C / 0.94 / 0.69
Deh / 0.35 / 0.07 / 0.51
BR / 0.53 / 0.42 / 0.54 / 0.64
β-G / 0.60 / 0.80 / 0.36 / -0.27 / 0.17
Phos / 0.49 / 0.52 / 0.40 / 0.64 / 0.79 / 0.42
Pol Ox / -0.02 / 0.19 / -0.18 / -0.56 / -0.73 / 0.50 / -0.27
Ur / 0.48 / 0.70 / 0.25 / 0.12 / 0.44 / 0.82 / 0.81 / 0.26
G+ / -0.59 / -0.38 / -0.66 / -0.59 / -0.92 / -0.04 / -0.53 / 0.80 / -0.14
G- / 0.18 / 0.37 / 0.00 / -0.30 / -0.31 / 0.54 / 0.09 / 0.70 / 0.48 / 0.47
Fungi / 0.23 / 0.25 / 0.18 / -0.30 / -0.56 / 0.45 / -0.24 / 0.83 / 0.15 / 0.55 / 0.67
Bact / -0.56 / -0.34 / -0.64 / -0.59 / -0.91 / 0.00 / -0.51 / 0.82 / -0.10 / 0.98 / 0.52 / 0.57
Sat / -0.38 / -0.50 / -0.23 / -0.11 / -0.78 / -0.45 / -0.62 / 0.45 / -0.56 / 0.68 / 0.24 / 0.56 / 0.67
Mon / -0.44 / -0.13 / -0.62 / -0.77 / -0.68 / 0.36 / -0.30 / 0.79 / 0.22 / 0.84 / 0.61 / 0.48 / 0.85 / 0.26
WS-P / 0.35 / 0.26 / 0.36 / 0.56 / 0.95 / -0.02 / 0.67 / -0.84 / 0.28 / -0.89 / -0.42 / -0.75 / -0.89 / -0.79 / -0.67
pH / -0.16 / 0.07 / -0.31 / -0.45 / -0.72 / 0.40 / -0.18 / 0.96 / 0.29 / 0.86 / 0.67 / 0.74 / 0.88 / 0.47 / 0.81 / -0.81
WS-C / 0.49 / 0.43 / 0.46 / 0.32 / 0.83 / 0.31 / 0.64 / -0.52 / 0.47 / -0.73 / -0.05 / -0.43 / -0.71 / -0.71 / -0.35 / 0.82 / -0.56
C org / 0.46 / 0.28 / 0.54 / 0.72 / 0.93 / 0.06 / 0.72 / -0.72 / 0.32 / -0.89 / -0.38 / -0.53 / -0.89 / -0.65 / -0.72 / 0.84 / -0.71 / 0.68
C/N / -0,28 / -0,58 / -0,01 / 0,51 / 0,16 / -0,89 / -0,18 / -0,72 / -0,70 / -0,32 / -0,67 / -0,54 / -0,36 / 0,21 / -0,65 / 0.30 / -0.64 / -0.04 / 0.27

Statistically-significant correlation coefficients are shown in bold (P<0.05; Tukey HSD test). HS-C (humic substances carbon), FA-C (fulvic acid content), HA-C (humic acid content), Deh (dehydrogenase act.); BR (basal respiration); β-G (β-glucosidase act.); Phos (phosphatase act.); Pol Ox (polyphenol oxidase act.); Ure (urease act.); G+ (Gram-positive bacteria), G- (Gram-negative bacteria); Bact (bacteria); Sat (saturated); Mon (monounsaturated); WS-P (water-soluble polyphenols); WS-C (water-soluble Carbon); C org (organic Carbon).

Figure 1S. Litter characterization of each experimental tree diversity level.

Figure 2S. 13C-NMR spectra for litters at different soil sites