LAUSR

Simple Summary Model tests under laboratory conditions are very common in soil ecology and microbiology, but few of them are related to flooding, and comparison of the results of such an experiment with natural conditions is unprecedented. The present study investigated the basic parameters determining the biological activity of soil subjected to flooding under laboratory and natural conditions. The results obtained show that soil inundation under both natural and laboratory conditions significantly affects soil fertility and processes. The changes are more pronounced in the laboratory experiment than in the field conditions. Nevertheless, model studies are needed in environmental ecology and microbiology to predict changes under different stress factors, but their scale and pathway must be carefully planned. Abstract Studies using soil microcosms are very common, but few involve flooded soils, and comparing the results from such an experiment with natural conditions is unheard of. In the present study, we investigated the biological activity of soil (pH value, dehydrogenases and phosphatase activities) and the metabolic potential (EcoPlate™ Biolog®) of soil microorganisms in three fluvisol subjected to flooding under laboratory and natural conditions. The results indicate that soil flooding under both natural and laboratory conditions affected soil pH, enzymatic activity and metabolic potential (AWCD, average well colour development) of soil microorganisms. Changes in these parameters are more pronounced in the microcosmic experiment than in the field conditions. Furthermore, depending on the characteristics of the soil (i.e., its type, structure, vegetation) some of the soil quality parameters may return to their preflood state. Microcosm studies are needed in environmental ecology and microbiology to predict changes due to various factors, but their scale and course must be carefully planned.