The rhizosphere is a dynamic environment in which many parameters may
influence biogenicity. The important factors determining the microbial
community in the rhizosphere are plant and soil nutrient supply. The aim of
this paper was to determine the abundance of basic microbiological groups in
the rhizosphere of four wheat subspecies, in three fertilization treatments
in the organic farming system. A field experiment was conducted using a
randomized complete block design with four replicates. It was carried out on
the leached chernozem soil type. There was significant variability in the
abundance of the studied physiological groups of microorganisms between the
wheat subspecies, as well as between the fertilization treatments. The
rhizosphere of common wheat had the greatest abundance of fungi (24.37 x 103
g-1). The rhizosphere of compactum wheat had the largest abundance of
oligonitrophilic bacteria (361.47 x 105 g-1) and amonificators (119.27 x 105
g-1). There were no significant differences in the abundance of
actinomycetes between the cultivars of common, compactum and durum wheat,
but their lowest number was found in the spelt wheat cultivar (11.25 x 103
g-1). The combined application of biofertilizer and organic fertilizer
resulted in a significantly greater abundance of amonificators (56.6%),
fungi (28.2%) and oligonitrophiles (14.6%) than in the control treatment.
The results show that the crop variety and application of appropriate
fertilizer formulations can influence the abundance of the studied groups of
microorganisms. This is particularly the case in organic farming, which
relies completely on natural resources and processes.