COLLUVISOLS UNDER CULTIVATION IN SCHLESWIG-HOLSTEIN .2. CARBON DISTRIBUTION AND SOIL ORGANIC-MATTER COMPOSITION

Soils under intensive cultivation have altered due to water erosion. This study was conducted to determine whether soil organic matter (SOM) composition of the colluvial source (Ap horizons) differs from the colluvial sink (M horizons). The SOM of a sandy Catena with erodic Cambisols and colluvic soils (Colluvisols) in Schleswig-Holstein, Northwest Germany, was investigated. A wet chemical analysis was combined with CPMAS C-13-NMR spectroscopy. In one case a significant correlation between the SOM composition of the Ap horizon of the erodic Cambisol and the M horizon of the Colluvisol was high (r2 = 0.904***), whereas the con-elation for the other set was much weaker (r2 = 0.640*). Two possible paths of pedogenesis are discussed. About 70 % of the SOM of the colluvial source is decomposed during translocation or after deposition. A selective preservation or new formation of humins in the M material is probable. These humins contain, obviously, large amounts of polysaccharides, which were not detected by the wet chemical analysis. Further investigations of colluvic and erodic soils are necessary in order to specify the SOM quality and its possible modification due to soil translocation and accumulation.