Maria Valeryevna Timofeeva

Methodological peculiarities of basal respiration (BR) measurement have been studied on the peat soil samples from two taiga subzones. It is found that the BR values at the initial incubation time (30 minutes) significantly exceed the ‘classical’ variant (24 hours) and gradually decrease with time. It is observed for all types of samples. The dependence of BR on the volume of the gas phase in the system was revealed - the values are higher the larger the volume of the incubation vial and the larger the ratio of the volume of the gas phase: mass (volume) of the sample. Initial values of CO2 concentration do not influence the dynamics of BR, because both at about zero and relatively high (4400 ppm) starting values of CO2 content the results of incubation were similar. It is critical to maintain the same incubation time interval, the same vial and sample volume while assessing the biological activity of soils using the BR method. The standard variant of BR determination during 24-hour incubation showed results that differed minimally depending on vial volumes and is probably preferable in this variant of experiments.