Is there a correlation among factors used to estimate soil microbial biomass?

Correlation among the flushes of CO2-C, mineral. N and ninhydrin-reactive N (NRN) following fumigation of fresh soils sampled at two depths were examined. Flushes were significantly correlated in the 0-15 cm depth of the two soils investigated. For these samples the relationship between biomass C (estimated by chloroform fumigation-incubation (CFI)) and the release of NRN was similar to that reported in the original methodology. The coefficients of correlation were, however, lower than those reported elsewhere with conditioned topsoils. Correlation among flushes was not significant in the 15-30 cm samples. The relationship between the release of NRN from fumigated soil with biomass measured by CFI may be strongest for soils and conditions similar to those from which the relationship was developed.