Microbial abundance in rhizosphere of medicinal and aromatic plant species in conventional and organic growing systems

Abstract

This study was aimed at comparing the abundance of microorganisms in the rhizosphere of four different medicinal and aromatic plant species (basil, mint, dill and marigold) grown under both conventional and organic management on the chernozem soil at the experimental field of Bački Petrovac (Institute of Field and Vegetable Crops, Novi Sad, Serbia). Two sampling terms (June 1 and July 18, 2012) were performed to collect samples for microbiological analyses. The microbial abundance was higher in organic than in conventional system while at the same time significant differences were obtained only with dill rhizosphere. The differences in number of microorganisms belonging to different groups relied upon both plant species and sampling term. Thus, in mint, the recorded number of azotobacters and fungi was significantly higher whereas the number of ammonifiers was significantly lower. The present results indicate that organic growing system affected the abundance of microorganisms in rhizosphere of species investigated, especially in the second term of sampling.

Cilj istraživanja bio je da se uporedno ispita brojnost mikroorganizama u rizosferi četiri lekovite i aromatične biljne vrste (bosiljak, pitoma nana, mirođija i neven) koje su gajene na konvencionalan i organski način na zemljištu černozem na eksperimentalnom polju u Bačkom Petrovcu (Institut za ratarstvo i povrtarstvo, Novi Sad, Srbija). Uzorci za mikrobiološku analizu uzeti su u dva termina (1. jun i 18. jul 2012. godine). Brojnost mikroorganizama bila je veća u organskom sistemu u odnosu na konvencionalni, ali je značajna razlika zabeležena samo za rizosferu mirođije. Razlike u broju mikroorganizama koji pripadaju različitim grupama zavisile su kako od biljne vrste tako i od termina uzorkovanja. Tako je na primer kod pitome nane zabeležen visoko značajno veći broj azotobaktera i gljiva, dok je broj amonifikatora bio značajno manji. Dobijeni rezultati ukazuju da organski način gajenja više utiče na brojnost mikroorganizama u rizosferi ispitivanih vrsta, posebno u drugom terminu uzorkovanja.