Saccharides in some Japanese paddy soils

Monosaccharides released by acid hydrolysis from paddy field soil, from the light and the heavy fraction of soil, front some plant fragment were determined using automated anio-exchange chromatography. Between 5 and 12 per cent of the organic carbon was present as saccharides. The monosaccharide composition of the different soils was very similar, in spite of differences in the absolute amount of saccharides present. The amount of the various monosaccharide in the whole soil was found to be in the order glucose»xylose galactose, mannose, arabinose rhamnose ribose. The monoccharide composition of the soils showed a marked contrast to that of the rice ra8ment, and partially decomposed plant remains taken from the soil. Glucose, xylose, arabi-the predominant saccharides in the rice fragments and the plant remains, while the amounts of galactose, mannose, rhamnose were negligibly small. It was found that the proportion of galactose, mannose, rhamnose and ribose in the heavy fraction Of soil was greater than that of glucose, xylose, and arabinose The present observation was in agreement with the view that soil sauharides comprised Pentoses originates in plant materials. The molar ratio of xylose to mannose was calculated to show the characteristics of the mono-saccharide composition of soils and some plant muerials.