Changes in the monosaccharide composition during the decomposition of straws under field conditions

Abstract

Changes in the monosaccharide composition during the decomposition of rice and barley straws under field conditions were examined. The proportion of mannose, galactose, fucose, rhamnose, and ribose increased consistently with time, whereas the proportion of cellulosic glucose became smaller consistently. Changes in the proportion of hemicellulosic glucose, arabinose, and xylose followed a somewhat zigzag course, though a consistent increase in the proportion of hemicellulosic glucose was observed after the flush of decomposition.The molar ratio of xylose to mannose decreased sharply at the flush of decomposition, then gradually afterwards, and reflected well the decomposition of the straw saccharides. The ratio of hemicellulosic glucose to cellulosic glucose became consistently larger with time after the flush of decomposition. Samples which contained less straw saccharides with the progression of the decomposition appeared to have larger molar ratios of hexoses to pentoses, deoxyhexoses to pentoses, and hemicellulosic saccharides to cellulosic saccharides.Even after 3 years of incubation, the monosaccharide composition of the straw, though more similar, was still quite different from that of soil, reflecting the persistence of the remaining straw saccharides.

Evolution of Concepts of Environmental Natural Nonliving Organic Matter

“…Sugar abundances ratios, such as (Mannose + Galactose)/(Xylose + Arabinose) and (Rhamnose + Fucose)/(Xylose + Arabinose), have been used to indicate the origins, plant or microbial, of sugars in soil saccharides (Oades, 1984 ;Murayama, 1984 ). The logic is based on the types of data, referred to above [and referenced in Clapp et al (2005) ], that indicate that xylose and arabinose are largely found in plants and that mannose, galactose, rhamnose, and fucose are more likely to be found in microbial cells.…”

Aspect-vegetation complex effects on biochemical characteristics and decomposability of soil organic carbon on the eastern Qinghai-Tibetan Plateau

“…According to Oades (1984), ratios of galactose + mannose to arabinose + xylose (GM/AX) <0.5 are indicative for plant-derived carbohydrates whereas those >2.0 signify a primarily microbial origin. Further, an increasing value of rhamnose + fucose to arabinose + xylose (RF/AX) reflects an increasing microbial carbohydrate synthesis (Murayama 1984).…”

Response of bulk chemical composition, lignin and carbohydrate signature to grassland conversion in a ley-arable cropping system

“…fucose)/(xylose ? arabinose) have been defined to discriminate between carbohydrates predominantly derived from plants (low ratios, \0.5) and microbial input (high ratios,[2; Murayama 1984;Oades 1984). …”