Soil Organic Matter Characteristics in Sporadic Permafrost-affected Environment (Creux du Van, Switzerland)

Figures & data

FIGURE 1 (A) Map of Switzerland with the study area indicated (46°56′N, 6°44′E), and (B) the study area (Creux du Van) and the position of the sampling sites within talus slope.

Table 1 Organic C forms (total organic C—TOC, dissolved organic C—DOC, microbial biomass C—C_micr, extractable C in 0.1 M NaOH solution—C_HA+FA, C content of fulvic and humic acids—C_FA and C_HA, and non-extractable C—C_NE) and N forms (total N—TN, dissolved organic N—DON, microbial biomass N—N_micr, extractable N in 0.1 M NaOH solution—N_HA+FA, N content of fulvic and humic acids—N_FA and N_HA, and non-extractable N—N_NE) in the Oa horizons of the stunted forest (site I) and reference forest (site II) located in Creux du Van (CH). Numbers in parentheses are the standard errors (n  =  3).

Table 2 Elemental composition (percentage expressed on a moisture- and ash-free basis), atomic ratio, optical density at 450 and 650 nm of alkaline HA and FA solution (E₄/E₆ ratio), and ash content of humic acids (HA) and fulvic acids (FA) extracted from the Oa horizons of the stunted forest (site I) and reference forest (site II) located in Creux du Van (CH).

FIGURE 2 FT-IR spectra of HA and FA extracted from the Oa horizons of the stunted forest (site I) and reference forest (site II) located in Creux du Van (CH).

Table 3 Δ¹⁴C, ¹⁴C-based age and mean residence time (MRT) of bulk soil and humic acids (HA) of the Oa horizons of the stunted forest (site I) and reference forest (site II) located in Creux du Van (CH). The data are reported as the mean of two replicates (reported in parentheses).

FIGURE 3 Van Krevelen diagram of HA and FA extracted from the Oa horizons of the stunted forest (site I) and reference forest (site II) located in Creux du Van (CH).