No abstract

A sensitive method for estimating living biomass, based on a direct extraction of phospholipids, was applied to soil. The variation between replicate soil samples was generally below 10%. Recovery from soil was qualitative. Estimates of biomass from the phospholipid assay were not correlated with estimates from the chloroform fumigation‐incubation method (CFIM). In non‐fumigated soil a significant reduction (25–57%) of biomass, as determined from phospholipid analysis, was observed during the 10‐day incubation. The concentration of phospholipids was reduced by 21–54% during the 24‐h chloroform fumigation, decreasing further during the 10‐day incubation. Phospholipid, carbon dioxide evolution and inorganic nitrogen were followed in a growth experiment with additions of glucose and glucose + ammonium. The conversion of phospholipids into biomass‐C units is discussed in relation to the observed ratios of phospholipid to CFIM biomass‐C, as well as to the ratios estimated from the growth experiment.