A Simple Method to Determine Soil Microbial Biomass Carbon by Facilitating Gaseous Diffusion of Chloroform into Pores

Abstract

Chloroform fumigation and extraction (CFE) has been a widely accepted method for quantifying overall size of soil microbial community, which is a key indicator to assess the quality and health of a given soil. However, the standard procedure of CFE requires careful operations to generate enough CHCl 3 vapors and flush them into soil pores. We suggest a new simple alternative for facilitating gaseous diffusion of CHCl 3 molecules under ambient air pressure conditions. The microbial C values by the new approach, examined for several farmland, forest, and grassland soils, coincided well with those obtained by the standard CFE. The cell lysis and extraction coefficient was also close to that of standard CFE and much higher than that evaluated for a liquid-based CHCl 3 cell lysis.