In contrast to whole bacterial communities, actinomycetes
responded to medium enrichment with composted
pig slurry by intensive development. This was particularly
evident in the R1 zone of a rooted plant, where
on average over 130 x 106 CFU of actinomycetes were
found in the medium with compost as compared to about
70 x 106 in 1 g d.w. of the control medium. That may
prove that composted pig slurry has a positive influence
on multiplication of plant growth-promoting rhizobacteria
(PGPR), among which one of the most important
groups is constituted by actinomycetes [1]. The value of
a rhizosphere effect for actinomycetes amounted to 4.8
when geranium was grown on the medium with compost
and to 2.7 when geranium cuttings were grown on the
medium alone (Fig. 3). This indicated a strong synergic
effect of compost and a rooted plant on the development
of actinomycetes within its rhizosphere