Effect of vermicompost on changes in the bacterial community in maize rhizosphere Vplyv vermikompostu na zmeny bakteriálneho spoločenstva v rizosfére kukurice

The aim of the study was to observe changes in the diversity of bacterial community in maize rhizosphere influenced by organic and mineral fertilization. Four variants of fertilization were tested vermicompost (VC) at recommended annual dose 40t*ha, doubled annual dose of VC, recommended dose of ammonium saltpeter with dolomite (LAD 27) and combination of VC and LAD 27. Experiment was conducted with potted maize plants in controlled conditions of greenhouse during 74 days. Using PCR-DGGE method, we investigated differences in total bacteria community as well as in community of ammonia oxidizing bacteria. Based on occurrence of operative taxonomic units (OTU) we found differences in bacterial species spectra among fertilization variants. The highest Shannon ́s biodiversity index was observed in variant with VC addition in dose 80 t*ha.The fertilizers effect on diversity of ammonia oxidizing bacteria was not significant however in each variant with vermicompost addition was the occurrence of new specific OTU observed. This OTU was identified as Nitrosospira sp. It was proven that some bacterial species introduced to soil with vermicompost addition can survive for at least 74 days and these bacteria can influence basic functions of soil microbiocenosis in nitrogen cycle.