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

Soils under intensive cultivation have altered due to water erosion. T his study was conducted to determine whether soil organic matter (SOM) composition of the colluvial source (Ap horizons) differs from the co lluvial sink (M horizons). The SOM of a sandy Catena with erodic Cambi sols 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 bet ween 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 possi ble paths of pedogenesis are discussed. About 70 % of the SOM of the c olluvial source is decomposed during translocation or after deposition . A selective preservation or new formation of humins in the M materia l is probable. These humins contain, obviously, large amounts of polys accharides, which were not detected by the wet chemical analysis. Furt her 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.