A comparison of phospholipid and chloroform fumigation analyses for biomass in soil: potentials and limitations
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. © 1991.