The PLFA analysis gives insight into the biomass of the active mycelium (network of hyphae) of arbuscular mycorrhiza. These fungi live in symbiosis with plant roots and thereby increase the root surface of the plant. In exchange for sugars, the plant receives water and nutrients, such as phosphorus and potassium, from the mycorrhizal fungi. Crops that are not able to form a symbiosis with arbuscular mycorrhiza include cruciferous (e.g. cabbage and yellow mustard) and the goosefoot family (e.g. spinach and beet).