Abstract

Between soil organisms, various interspecific relationships are formed, some of which are positive, and others are negative for at least one of the parts involved. A mutually positive relationship is symbiosis. Endo- and ectosymbioses between nitrogen-fixing bacteria and plant roots, actinorrhizae, and, most of all, mycorrhizae play extremely important roles in plant productivity and maintaining soil quality. Relationships between plants and various groups of microorganisms at the rhizosphere level also ensure a matter and energy flow from one plant to another, leading to a true ''mycorrhizal Internet”. Knowledge and control over these complex relationships also have practical applications, in producing biofertilizers, biopesticides, and in bioremediation, etc.