Les phénols de la lignine et le 13C, traceurs de l'origine des matières organiques du sol

Abstract In spodosols of Gascony (France), conversion of maritime pine stands into maize cropping leads to an incorporation of maize organic matter, which changed the isotopic (δ13C) and phenolic signature in A and L horizons of soil. Hydrolysis of phenol lignin in forests and cultivated soils showed the predominance of vanillic units under forest and the early but moderate incorporation of cinnamic acids. Incorporation of syringic units appeared higher, related to a large maize production of stable syringic phenols. Syringic units represented a long-term marker of maize inputs in soils, whereas vanillic units revealed the degradation of forest organic matter.

Geochemical characterization of soil organic matter and variability of a postglacial detrital organic supply (chaillexon lake, france)

Sulphur Stored in Forest Soils and the Relative Importance of Organic and Inorganic Forms. Examples from Mont-Lozère (Southern Massif Central)

From studies initiated in 1981, the mean annual hydrochemical budget established in three experiment watersheds at Mont-Lozere demonstrated that sulphur is retained in soils and in arenaceous formations (Lelong et al. 1990). Soils were developed on weathered granite materials that were strongly reworked by periglacial processes. One watershed is covered with grasses (Bassin de la Cloutasse) and the two others by forest. A beech coppice (Fagus sylvatica L.) and a Norway spruce forest (Picea abies (L.) Karst., hereafter shortened to “spruce”) occupy the Bassin de La Sapine (54 ha) and the Bassin of La Latte (20 ha), respectively. Unfortunately, as a result of a parasite attack, a large part o…

The Relations between the Sulphur Forms and the Organic and Mineral Components in Soils Developed under Spruce Forests in the Mont Lozere (France)

Mean interannual (1981–1985) hydrochemical input-output budgets indicate net gains of sulphur in forested and unforested watersheds (1150–1450m deviation range) of Mont Lozere (2). The values of the sulphur gains, ranging from 5 to 10 kg/ha/yr. according to the watersheds are underestimated, since dry deposition is not considered in the budgets (1). It is now well known (3,4) that sulphur accumulation in forest catchments is mediated physically by sulphate adsorption on mineral amorphous surfaces and microbially by incorporation of sulphur into soil organic matter. To get a better assessment of these processes, in order to foresee their long term effects upon the proton-budgets and biogeoch…

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

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 Lozere. 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 …