Distribution of Amino Sugars in Mollisols in the Northeast of China

Amino sugars are predominant products of microbial origin. Analysis of amino sugars can elucidate the role of microbes in soil organic matter turnover; identifying the amino sugar pools in soils may give our knowledge on microbial- derived substances. To evaluate the accumulation and distribution pattern of amino sugars along a climo-sequence in the Mollisol region situated in the Northeast of China, samples from 43 surface (0-20 cm) soils were analyzed for their contents of glucosamine (GlucN), galactosamine (GalN) and muramic acid (MurAc) under a climate with the mean annual temperature (MAT) ranged from 1.8 to 7.2degC and a mean annual precipitation (MAP) from 322 to 703 mm. Amino sugar contents (mg kg^-1 soil) varied significantly among samples and were influenced by the mean annual temperature (MAT), and the clay and silt contents. The relationship between the ratio of amino sugar-N to total N (%) of the soil and MAT was negatively correlated, which followed the anti-parabolic relation model. The contents of total amino sugars in Mollisol increased with decreasing MAT. The amino sugars enriched in soil organic matter (SOM) were insignificantly different in different sites. The GlucN to GalN ratio and GlucN to MurAc ratio suggest that bacterial derived amino sugars are dominant in arable land in the Mollisol region.