PURPOSE: To obtain a vesicular-arbuscular(VA) mycorrhizal fungus formulation, preservable for a long period without requiring special equipment or method even at ordinary temperature and useful in the field of agriculture, horticulture, landscape architecture, civil engineering, etc., by using a fully aged compost having a specific moisture content as a carrier for VA mycorrhizal fungi.

CONSTITUTION: Surface layer soil of soybean farmland is collected and spores of VA fungi are collected by a wet sieving method. Thereby, spores of Gigaspora.margarita and Scutellospora.gregaria are obtained, proliferated and further mixed with fallen leaves of a broadleaf trees such as Quercus serrata or Quercus acutissima, corn, cattle feces, poultry manures, etc., allowed to stand for 1 year, remixed, allowed to stand, humified and aged for total 3 years. The resultant prepared fully aged compost with ≤50% moisture content is mixed with the VA fungal spores, placed in a bag made of an aluminum laminated film and preserved at 4°C for 4 days, subsequently sterilized at 250°C under dry heat conditions and regulated to 28% moisture content. An inorganic carrier is then added and mixed to afford the objective VA mycorrhizal fungus formulation using the fully aged compost as a carrier for the VA mycorrhizal fungi.