Plant carbohydrates depend on texture type, being higher for loamy sand than silt loam [117]. Carbohydrates play an important role in the formation of stable aggregates [118]. Fungi increase aggregate stability, due to a supply of enough extracellular polysaccharides [119]. On the other hand, Adesodun et al. [115] reported that aggregate stability correlated very poorly with carbohydrates fractions. Aggregate stability seems to better correlate with carbohydrates in hot water or dilute acid extracts, indicating suitability of these types of extracts to indicate changes in soil due to land use change [120].Microaggregates (20�C53��m) had a higher ratio of mannose plus galactose/arabinose plus xylose than other aggregate fraction of larger sizes up to >212��m (macro- and meso-), indicating the importance of microbial processes.

Solomon et al. [14] reported an increase of neutral sugars and uronic acids in particle size fractions, in the order silt < coarse sand < fine sand < clay. Soil organic matter in nano-size structures isolated from a clay fraction accumulated carbohydrates between groups of other compounds (N-heterocyclics, peptides, and alkyl aromatics) [121]. Puget et al. [122] found increasing carbohydrates with aggregate size, clay, and silt fractions within stable aggregates.3.2. Carbohydrates in Different Soil Types and DepthsSoil type has an impact upon sugar synthesis by microorganisms, reflecting microbial biodiversity and varied ecophysiology between soils. Derrien et al. [123] quantified sugar synthesis in soil from 13C labelled substrates using compound-specific isotope ratio mass spectrometry.

The Entinostat authors reported that the quality of added substrate (mono- and polysaccharide or amino acid) had little effect upon sugar production in soil.The concentration of carbohydrates generally decreases with soil depth [105, 124]. Carbohydrate content decreased from litter to soil organic matter and aggregates with incorporation of soil [125]. Carbohydrates can accumulate in horizons with strongly humified organic matter probably due to the toxic effect of adsorption to some oxides or hydroxide minerals, especially those with aluminium content. Minerals such as ferrihydrite and aluminium hydroxide reduced carbohydrate decomposition by 15�C50% [124].Osono et al. [126] reported a higher content of soluble carbohydrates in bleached litter colonised by Clitocybe sp. than in nonbleached litter. Carbohydrates are amongst the more rapidly degraded compounds of plant litter, resulting in organic matter being more enriched in lignin-derived compounds [127]. The ratio of selected hexoses to pentoses in needles was 1�C15 times lower compared to decomposing litter [128].Rumpel et al.