Native forests have been suffering changes, such as fragmentation and edge effect, and these have implications for the dynamics of carbon within the same fragment, differentiating vegetation and soil. In this way, the work aimed to evaluate the hydro-microbiological attributes of the soil in rainy and dry periods, as well as to indicate if there is an edge effect in a seasonal semideciduous forest fragment. The study was carried out in a forest fragment in the area of the State University of Goiás, Ipameri Campus, consisting of three transects divided into three blocks from the edge. Sampling was performed in two periods of the year, rainy and dry, to determine the gravimetric soil water content (UG), microbial biomass carbon (MBC), basal respiration (BR), and the metabolic quotient (qCO2). The data were subjected to analysis of variance (F test), and when significant, the means were evaluated by the Tukey test at 5% probability. Response variations of microorganisms are closely related to the periods studied; the rainy season benefits the carbon incorporation activity, and the dry season stimulates the carbon release. Consequently, metabolic efficiency is more pronounced in the rainy season. The edge of the fragment only influenced the MBC, evidencing that disturbances caused at the extremity of fragment interfere with the C input in the microbial biomass.