Microbial Glucosamine, Galactosamine and Muramic Acids in Some Canadian Agricultural Soils.

Amino sugars (ASs) are an important component of soil organic matter, with concentrations in soil up to 40 times greater than the concentration of living microbial biomass. In addition, amino sugars are potentially useful for tracking changes in microbe composition through time due to their various origins and slower turnover rates relative to living microbial biomass. Hence, the concentration and composition of amino sugars are important determinants of the amount, quality, and characteristics of soil organic matter. The objectives of this presentation are to: (i) examine the variations in the concentrations of amino sugars in soils collected from various sites, including Agassiz in BC (80 samples), Lethbridge in AB (56 samples), Woodslee (50 samples) and Ottawa (30 samples) in ON and Québec city in QC (60 samples); (ii) examine the effect of fertilization (organic or chemical), relative to non-fertilized control, on the accumulation of amino sugars in soils. We found that (1) total ASs varied from 700 to 6746 mg kg^-1 and Glucosamine (GluN) was present in the highest concentrations (485–4034 mg kg^-1) followed by Galactosamine (GalN) at intermediate concentrations (188–2051 mg kg^-1) whereas Muramic acids (MurA) had the lowest concentrations (0-190 mg kg^-1) amongst all samples. (2) The highest AS concentrations occurred in the samples of Lethbridge, AB and Agassiz, BC and the lowest AS concentrations were found in the samples of Woodslee and Ottawa, ON. (3) The AS concentrations for the soils of Québec, QC were in the between. Although Québec soils had a lower total AS concentration relative to Lethbridge soils, the former had a different pattern in individual amino sugar concentrations (lower in GluN and MurA but higher GalN), compared with the latter. (4) The average of GluN:GalN ratio was 1.87, varying from 1.70 to 2.00, for the all soils except for the Lethbridge soils which had the highest GluN:GalN ratio of 2.28. The Lethbridge soils also showed highest MurA concentrations, followed by the Agassiz soils, and the sandy soil of Québec. However, no MurA was detected from two Ontario soils (Woodslee and Ottawa, ON) and the clay loam soil of Québec City, QC. Both inorganic fertilizer and organic amendment increase individual amino sugar concentrations. However, the influence was generally lower for chemical fertilizer than organic amendments. The influences of organic amendments also vary with the types of amendments.