NOVELTY - A raw material mixture of decomposed organic substance and an additive mixture of enzyme and enzyme activator are stirred in a fermentation tank (3) with the monitoring of the water content of the mixture. A circulation path (33) circulates the mixture from the lower to the upper part of the fermentation tank and a switching valve (33) ejects externally the obtained fermented compost.    DETAILED DESCRIPTION - A raw material mixture containing decomposed organic substance is obtained and the water content of the mixture is measured and adjusted. An additive mixture containing an enzyme and enzyme activator are stirred with the raw material mixture in a fermentation tank (3) and the water content of the mixture is monitored. A circulation path (33) circulates the mixture from the lower to the upper part of the fermentation tank. A switching valve (34) in the circulation path ejects externally the fermented compost.    An INDEPENDENT CLAIM is also included for the apparatus for manufacturing the fermented compost. The apparatus consists of a compost tank (11), a decomposing tank (12) and a raw material supply unit (1). The raw material supply tank (1) has a metering zone (15), a grinder (16), a mixer (17) and a transport path. An additive supply unit (2) comprising a mixer, metering zone and transport path for enzyme and enzyme activator is provided. The raw material supply unit and the additive supply unit have a transport path which enables the mixing of the raw material and the additive in the vertical fermentation tank. The vertical fermentation tank has a mechanism to control internal temperature and water content. The circulation path circulates the mixture from the lower to the upper part of the fermentation tank. A switching valve provided in the middle of the circulation path ejects externally the obtained fermented compost.    USE -   For converting sour soil to alkaline soil.    ADVANTAGE -   The fermented compost is manufactured in a short time by the automated process. Manufacturing conditions such as water content, weight, temperature and time are monitored and adjusted. Generation of foul odour during compost manufacture is prevented by enzyme addition. The fermentation tank is vertically arranged and requires less installation area.    DESCRIPTION OF DRAWING - The figure shows a schematic diagram of the apparatus for manufacturing the fermented compost. (1) Raw material supply unit; ; (2) Additive supply unit; ; (3) Vertical fermentation tank; ; (11) Compost tank; ; (12) Decomposing tank; ; (15) Metering zone; ; (16) Grinder; ; (17) Mixer; ; (21) Enzyme pool; ; (22) Enzyme activator pool; ; (25) Additive transport mechanism; ; (33) Mixture circulating path; ; (34) Switching valve.