Mycorrhizal fungi occur in most biomes on earth and are a fundamental reason for normal plant growth and development on the planet. These fungi colonise plant roots, extending the root system into the surrounding soil, via a network of extensive fungal filaments (up to 50 m per gram soil). These filaments extract nutrients and water from a large soil volume and exchange them for carbon from the plant.

The secondary root system enables the linkage of many plants in a habitat and results in a stable plant community, while simultaneously supporting greater plant bio diversity. This network, when established, links the root systems of adjacent plants and probably helps share, more efficiently, scarce nutrient resources throughout the plant community.

In natural ecosystems or low-tillage agriculture, young seedlings can germinate and effectively ‘plug’ into this already established ‘motorway’ of mycorrhizal hyphae which permeates the soil, thus encouraging plant diversity in the community.