Distribution of sulphur forms in soils from beech and spruce forests of Mont Loz�re (France)

Abstract

From a quantitative inventory of sulphur forms and sulphur budget, the relation between the distribution of the various sulphur forms and the sulphate fluxes in three soil profiles has been addressed. These profiles are located in two forested watersheds at Mont Loz6re. One has been sampled in a beech forest and the other two in a spruce forest and in a harvested plot of this spruce forest, respectively. The mean annual input-output budgets showed a sulphur immobilization in the soil cover of the three plots. In the preserved spruce forest plot, because of larger dry depositions, the sulphur immobilization is much greater than in other plots and occurs essentially in the B horizons. In the other two profiles, the dominant immobilization occurs in the parent material.The total sulphur content is very high in the forest floor reaching 2065 txg S g-1 in the litter of one of the soils under spruce. In the organo-mineral horizons of soils under spruce, the total sulphur content decreases with depth and ranges from 310 to 520/xg S g-I in the A horizons to 100-200/xg S g ~ in the parent material. In the profile under beech, the total sulphur content is lower except in the parent material. In all cases, the organic sulphur is the major part of sulphur often representing more than 90% of total sulphur. In organo-mineral soil horizons of the spruce forest, the part of the sulphateesters is more important than in the soil of the beech forest, probably related to the different nature of the microbial activity in the spruce forest. In contrast, the humification processes are more efficient in the soil under beech, which can be due to the greater input of organic sulphur by litterfall. It appears that the dominant organic sulphur form varies as a function of microbial ecology and sulphate flux. The maximum of the inorganic sulphate is located at the base of the B horizons in the soil of the spruce forest and in the parent material of the soil under beech. In these horizons, the high content of inorganic sulphate can be related to the higher amounts of amorphous Fe and AI phases.

Spodosol–Histosol evolution in the Krkonoše National Park (CZ)

“…In MD1, the horizons above the spodic ones showed fulvic materials of small dimensions and appreciable contents of carboxyl groups, as evinced by the E 4 / E 6 ratio and FT-IR spectra (band at 1720 cm À 1 , due to COOH CjO stretching, Figs. 1 and 2 evinced by the E 4 / E 6 ratio if compared with the O / C may be related to the high contents of S (Table 4), that causes molecular condensation and weight increase (Vannier et al, 1993). Very high S contents were in fact found in the FA from the superficial organic horizons of MH2, MH3 and MH4 (Table 4) if compared to the amounts reported in the literature (Schnitzer, 1991).…”

Structural characterization of aquatic humic substances ? The need for a multiple method approach

“…)Abbt-Braun and Jahnel, 2001; 2) Vanier et al, 1993; 3) Strehl and Prietzel, 1999; 4) Jahnel et al, 2002; 5) Xia et al, 1998Xia et al, , 1999 …”

Temporal trends in chemical parameters of upland forest soils in southern Finland

“…However, there was an increasing trend in the extractable S concentration in the 0-30 cm mineral soil. The B horizon in the mineral soil has a relatively high sulphate-adsorption capacity (Singh 1980, Autry et al 1990, Vannier et al 1993, and the retention of sulphur in the aboveground parts of the ecosystem and its subsequent release over the years could explain the continuous accumulation of sulphur in the mineral soil.…”