抄録
To obtain fundamental information on the nature and properties of sediments in dammed lakes, we investigated various properties of sediment from dammed Lake Ono using soil scientific methods. Furthermore, the Lake Ono sediment was characterized by comparing its various properties with those of yellow soil. 1) Lake Ono is a eutrophic lake which phosphorus is a limiting factor. 2) The pH, exchangeable base content, and degree of base saturation of the sediment were much higher than those of the soil. 3) The clay content of the sediment was 2 times higher than that of the soil. The texture of the sediment was Heavy clay (HC), while that of the soil was Clay loam (CL). There were no large differences on organic carbon and total nitrogen contents, and the C/N ratio between the sediment and the soil. 5) The “combine”-form humus content of the sediment was higher than that of the soil. The reverse was true for the “free”-form humus content. 6) The X-ray diffraction patterns of the clay fraction of the sediment were almost the same as those of the clay fraction of the soil. 7) The elemental composition and 13C-NMR spectrum of the fulvic acid isolated from the sediment were similar to those of the soil. On the basis of the present findings and previous information on the properties of soil distributed in catchment areas, it was assumed that the Lake Ono sediment is strongly affected by soil particles and Ca in its catchment areas, which flow into the lake.
