A Research on Mechanism of Decomposition and Reduction of Organic Soil Accompanying Root-matting in Rhizosphere of Reed

点击翻译按钮获取中文摘要

With growth in the rhizosphere of reeds, it has been observed that their rhizomes and roots are spread around in all directions and replace the soil, the root-matting. The mechanism of decomposition and reduction of the organic soil accompanying the root-matting was studied. Four experimental pots in which contained the soil dredged from an eutrophic lake were used, and 30 reeds which budded from a seed were transplanted and were grown in the every pot.The pattern of the increase in a ground part and an underground part of the reeds was able to be expressed using the T/R ratio which is a dry weight ratio of a ground part to an underground part. It was suggested that relevance had quite a few change of this T/R ratio with the pattern of a reduction of the organic carbon in soil.The rise and fall of the organic matter in the reed-bed soil could be expressed with the mass balance model consisted of the organic supply and the bacterial organic decomposition. The organic matter was supplied by exudation into the soil accompanying transportation and storage of the photosynthetic products from a ground part to an underground part, and by release accompanying decomposition of an underground part. Bacterial organic decomposition took place under the aerobic condition in soil even without planting the reeds. However, diffusion-supply from a ground part to the root area with planting the reeds raised a microbial organic decomposition.At older aged reeds, organic reduction was shown to become easy to take place at the time of budding in spring, because that the decomposition stood high rather than supply of organic matter in quality. Moreover, it was suggested the possibility of development of the technique of promoting organic matter decomposition in soil by control of mowing time, while suppressing the organic matter supply from a ground part.