Anomalies in microbial biomass measurements in acid organic soils using extractable carbon following chloroform fumigation

Two experiments showed that the chloroform fumigation-extraction (CFE) method is unreliable in wet soils of high organic content. The first experiment which applied the CFE method to a defined 14C-labelled biomass showed that the 0.5 M K 2SO 4-extractable C flush was not originated by lysed biomass. In the second experiment, direct observation of protozoan cells showed their preservation after chloroform fumigation. It is suggested that the high water content of the soil protected the cells against lysis because of the low solubility of chloroform.