Soil is a complex ecosystem whose functionality is related to the links that exist between chemical, physical, biological parameters and microbial communities. Our purpose was to carry out an analysis of variance of chemical properties of the soil in relation to the vegetation period. The analysis of the soil gives us knowledge about the fertility status of the soil, which is closely related to the nutritional status of plants. The analysis involved urban soil, agricultural soil and greenhouse soil from Dobrogea area. Soil samples come from the urban area: Constanta, agricultural area: Ciocarlia de Sus and greenhouse:Cumpana. To estimate the seasonal changes in the soil, three periods were studied: before vegetation (sowing), after the vegetation period (harvesting), relative rest period (winter). The chemical parameters evaluated were: soil reaction pH (acidity degree), conductivity - as an indicator of the nutrients available in the soil (soluble salts), ion exchange capacity (cations and anions), organic matter (humus), nitrogen content (total nitrogen and nitrites), the amount of extractable iron. The pH values were in the range corresponding to the weak acid-neutral soil for all three types of sample soils, with slight variations from one period to another while the recorded conductivity values indicate that the analyzed soils belong to the category of non-saline soils. The analyzed soil samples presented low concentrations of nitrites and the assimilable iron content was in the range 48.81 - 259.12 ppm.