Total carbohydrates of the soil microbial biomass in 0.5 M K2SO4 soil extracts

The relationship between total carbohydrates and organic C found in the extracts of non-fumigated soils and in the extractable fraction after CHCl3 fumigation was investigated in a group of 58 arable, 24 grassland and 26 forest soils. We evaluated also the effects of soil conditions and the form of land use on these relationships. The content of microbial biomass carbohydrate C (E(CHC)) ranged from 4.3 to 261.4 mu g C g(-1) soil and was significantly correlated (r = 0.88) with microbially-derived C (E(C)). The E(CHC)-to-E(C) ratio was mainly affected by the pH but also by soil organic C and total N, but not directly by the form of land use. Due to the large, pH-dependent variations in the E(CHC)-to-E(C) ratio, no conversion factor can be proposed for the estimation of biomass C by measuring carbohydrate C. For this reason, the possibility of monitoring shifts in the microbial community structure seems more valuable. Copyright (C) 1996 Elsevier Science Ltd