Mycorrhiza – a beneficial fungus

A major part of the soil microbial biomass is composed of fungi. Important representatives of
the soil fungi are the "mycorrhizae" that live in association (symbiosis) with plant roots. Both
the plant and the fungus profit from the association: the plant gets nutrients collected by the
fungus and the fungus receives assimilates ("food") from the plant in exchange. Mycorrhizae
are present in all types of soils, but not all crops can get into a symbiosis with the fungus.
Mycorrhizae have several functions, which are of high interest for the farmer:
They enlarge the rooting zone of plants and can enter into small soil pores
They dissolve nutrients such as phosphorus from mineral particles and carry them to the
plant
They make soil aggregates more stable thus improving the soil structure
They preserve moisture and improve the water supply to the plants
Mycorrhiza formation depends on the soil conditions, the crops that are grown and the
management practices:
Soil tillage and burning of biomass drastically harm the mycorrhizae
High nutrient levels (especially phosphorus) and chemical pesticides suppress the symbiosis
Mixed cropping, crop rotation and the cultivation of perennial plants encourage mycorrhiza
Practice mulching to stabilize soil temperature and moisture
Among the naturally occurring species of mycorrhizae, not all show the same efficiency to
take up phosphorus from the soil. That is why artificial inoculation of specific mycorrhiza
varieties can improve their use. Inoculation, however does not reduce the importance of
offering appropriate living conditions for these organisms.