PURPOSE: To obtain combustible artificial culture soil for solving soil embarrassing a person with its final disposal at a breath by burning it as dust in agriculture on the roof and a veranda in a big city.

CONSTITUTION: This combustible artificial culture soil comprises a symbiotic mixed culture product of Thermoactinomyces SK053 (FERM P-13,598), a new thermophilic actinomyces and Clostridium thermocellum SK522, a thermophilic fiber decomposing bacterium or another fiber decomposing bacterium as an active ingredient and a ground material of a combustible and hardly decomposable fiber substance as a substrate. The combustible artificial culture soil which is humified by the symbiotic mixed culture of the new bacterium strains and aged has obtained good results of excellent growth and development of culture plant, high qualities and a good harvest.