Sanja Čekić and Zlatan KovaÄÂević
This paper shows the results of many years researches (2013-2014) of the weed vegetation of the Lijevče polje area which includes four associations: Panico- Galinsogetum parviflorae Tüxen at Becker 1942, Panico-Portulacetum oleraceae Lozanovski 1962, Cynodono-Sorghetum halepense (Laban 1974) Kojić 1979 and Erigerono-Setarietum glaucae Šumatić 1997. Floristic- phytosociology researches were performed by the principles and methods of the Switzerland-French phytosociological school on 61 localities. By projecting the plant communities on the mail components (Principal Component Analysis) and comparting them to the ecological indices (variables), it shows that Panico-Galinsogetum parviflorae depends on humidity the (F) and the chemical reaction (R), while Panico-Portulacetum oleraceae shows the dependence on the nutrients (N). Association Cynodono-Sorghetum halepense shows the dependence on the temperature (T) and the light (L). Association Erigerono-Setarietum glaucae is separated because it develops on the stubble.