In this study, the changes in soil organic matter (SOM) and the possibilities of their monitoring in a shorter period of time by means of carbon parameters were followed. The experiment includes four ecosystems (forest, meadow, urban, and agro-ecosystem) on Haplic Chernozem (Močenok, Horná Kráľová, Trnava) and Haplic Luvisol (Ludanice, Veľké Zálužie, Lovce) of different localities. The objectives of this study were assessment of the differences in the stability of soil organic matter in different ecosystems and in soil types using labile forms of carbon and nitrogen, and also with dependence on particle size distribution. The highest contents of total organic carbon (TOC) and labile carbon (CL) were in a forest ecosystem, but in case of other ecosystems, the differences were determined only in the contents of CL. After forest ecosystem, the highest content of CL was in agro-ecosystem > meadow ecosystem > urban ecosystem. Based on parameter of lability of carbon (LC), the most labile carbon can be evaluated also in the forest ecosystem (0.209) > agro-ecosystem (0.178) > meadow ecosystem (0.119) and urban ecosystem (0.116). In the case of nitrogen, the differences were observed between the soils. Higher contents of NT and NL were recorded in Haplic Chernozen than in Haplic Luvisol. Contents of TOC (P < 0.05; r = -0.480), CNL (P < 0.05; r = -0.480), and NL (P < 0.01; r = -0.545) were in a negative correlation with the content of sand fraction. The values of studied parameters in meadow and urban ecosystems were relatively balanced, because in both cases, the vegetation cover were grass, pointing to a significant influence of vegetation on the parameters of SOM.
