Influence of Storage Methods and Pre-Incubation Periods of Soil Samples on Respiratory Activity

Abstract To improve methods of the storage and pre-treatment of soil samples, we studied the effect of their drying and freezing and of the duration of their subsequent pre-incubation on the basal and substrate-induced respiration of soils. Soils, differing in their formation conditions and undergoing intensive anthropogenic impact, were chosen for the study: an agrosoddy-podzolic soil Albic Glossic Retisols (Loamic, Aric, Cutanic) from Leningrad oblast, an agrochernozem Chernozem (Loamic, Aric) from Belgorod oblast, and urban soils (Urbic Technosol) from four main urban ecosystems (of major traffic artery and recreational, industrial, and residential areas) in Vasileostrovskii district of Saint Petersburg. Respiration was determined in fresh soil samples at natural moisture content (control), in air-dried samples stored at room temperature, and in samples frozen at –20°C for 14 days, following pre-incubation at 22°C and a soil moisture of 60% water-holding capacity after 3, 7, and 10 days. Drying of samples caused a statistically significant reduction in soil respiration activity and microbial biomass, regardless of soil type and pre-incubation duration. The effect of freezing on the respiration of the studied soil varied, but no significant changes were detected in most soil samples relative to fresh one.