Abstract: There are provided Bacillus macerans decomposing turf pseudo thatch and thatch, a microbial mixture composition comprising 1 part by weight of the Bacillus microorganism and 5 to 30 parts by weight of clay minerals, and a microbial material comprising at least one compound selected from the group consisting of 50 to 100 parts by weight of an ionic surfactant, 50 to 100 parts by weight of casein and 50 to 100 parts by weight of a casein hydrolyzate, and 50 to 200 parts by weight of sugars, in 100 parts by weight of said microbial mixture composition. This microbial material decomposes thatch by transferring not only to turf pseudo thatch but also to the soil, also decomposes pseudo thatch layers without exerting any adverse effect on the soil and environments for living creatures, and in golf courses, can promote growth of turf.