The Monosaccharide Composition of Polysaccharides in Ando Soils

Abstract

The monosaccharide composition of Ando soils, which originate from volcanic ash and have high organic matter content (8-21% carbon), was quite different from that of non-volcanic ash soils (1.2-1.9% carbon), being richer in mannose, fucose and ribose, whereas there was less glucose in cellulose-like form. arabinose, xylose and rhamnose. The Ando soils were also characterized by a lower percentage of organic carbon in the form of saccharide (4.4-7.4%) in comparison with non-volcanic ash soils (10.5%), though the former soils contain a greater amount of saccharides.The monosaccharide composition of Ando soils was unrelated to the vegetation, land usage, or climatic conditions, and is presumed to be a soil characteristic resulting from the preferential accumulation of microbial polysaccharides.

Persistency and monosaccharide composition of polysaccharides of soil which received no plant materials for a certain period under field conditions

“…For the release of monosaccharides, soil samples were hydrolyzed stepwise with 2.5 M H 2 S0 4 firstly as a primary hydrolysis, and with 0.5 M 11 2 50, after soaking with 13 M H 2 SO, as a secondary hydrolysis (20), essentially according to the procedure of 0ADES et al (25). The hydrolysate was neutralized with sodium hydroxide solution or Ba(OHh solution.…”

“…The ratio of the non-cellulosic to the cellulosic glucose (glucose(A)/glucose(D)) became larger on incubation. Considering the origin of the soil polysaccharides, the molar ratio of xylose to mannose was calculated by the author (19,20). The ratio for the upland field fell as the experiment progressed, but this tendency was not noticeable up to 18 months in the paddy field .…”

“…On the other hand, neutral saccharides account for a substantial part of the soil organic matter, e.g. 9-11% in non-volcanic ash soils, and 4-7% in Ando soils of volcanic ash origin (19,20). A buried humic horizon for which substantial geological time had elapsed, was;.also found to contain a substantial amount of saccharides (32).…”

“…The monosaccharide composition of soil hydrolysates is quite different from that of plant materials (2,19,20). Glucose, xylose and arabinose are the predominant components of plant polysaccharides, whereas soil polysaccharides contain in addition substantial amounts of mannose, galactose, rhamnose and fucose.…”

Relationship between neutral sugars and the degree of humification in Andisols

“…According to Murayama (1980), the amount of neutral sugars in volcanic ash soils which ranged from 4.4 to 7.4% of SOM was relatively small compared with 10.5% of SOM in non-volcanic ash soils. Moreover Murayama (1984b) and Folsom et al (1974) reported that the correlation between the amount of neutral sugars and total carbon (TC) was positively significant.…”