PURPOSE: To obtain a carbide of beer cake as an inexpensive porous material having uniform qualities useful as a soil conditioner having excellent environmental maintenance and safety by drying beer cake and carbonizing.

CONSTITUTION: Beer cake is dried, adjusted to ≤20, water content and carbonized in a fluidized furnace at 400-700°C to give the objective carbide of beer cake. The carbide of beer cake is preferably mixed with liquid fertilizer or one or more of fertilizer components such as urea, magnesium phosphate, ammonium phosphate or potassium phosphate.