An inter-laboratory comparison of gaseous and liquid fumigation based methods for measuring microbial phosphorus (Pmic) in forest soils with differing P stocks.

In an inter-laboratory trial, gaseous ("CFE") and liquid fumigation ("Resin") based methods for measuring microbial phosphorus (Pmic) were compared, based on the analysis of soil samples from five forests, which differ in their P stocks. Both methods reliably detected the same Pmic gradient in the different soils. However, when the individual recovery rates of spiked P were taken into account, the "CFE" based methods consistently generated higher Pmic values (factor 2) compared to the "Resin" based approaches.