ULTRAVIOLET ABSORBENCY (280 NM) OF COMPOUNDS RELEASED FROM SOIL DURING CHLOROFORM FUMIGATION AS AN ESTIMATE OF THE MICROBIAL BIOMASS

A rapid, inexpensive adaptation of the fumigation-extraction method fo r estimating the soil microbial biomass based on the fact that certain molecules absorb in the near ultraviolet (UV) region of the electroma gnetic spectrum is described. A highly significant, positive linear re lationship (r = 0.94**) between biomass C as measured by fumigation-e xtraction, and estimates of the microbial biomass organic matter as me asured by UV absorbance at 280 nm was obtained. Similarly, highly sign ificant relationships were obtained between UV estimates of the microb ial biomass and biomass total N and biomass ninhydrin-reactive N (r = 0.91** and r = 0.92*** respectively). (C) 1998 Elsevier Science Ltd. All rights reserved.