(1) Decomposed polysaccharides (starch, cellulose, hemicellulose) that do not contain nitrogen organic matter are first hydrolyzed into monosaccharides by hydrolytic enzymes secreted by microorganisms. Glucose decomposes rapidly under well ventilated conditions, and intermediate products such as alcohol, acetic acid, and oxalic acid are not easily accumulated, forming CO2 and H2O while releasing a large amount of heat energy. If ventilation is poor, under the action of anaerobic microorganisms, monosaccharides decompose slowly, produce less heat, and accumulate some intermediate products - organic acids. Under extremely anaerobic microbial conditions, reduced substances such as CH4 and H2 can also be generated.

(2) The nitrogen-containing organic matter in the decomposition compost includes proteins, amino acids, alkaloids, humus, etc. Except for humus, most of it is easily decomposed. For example, proteins are degraded step by step by proteases secreted by microorganisms, producing various amino acids, which are then converted into ammonium salts and nitrates through ammonification and nitrification, respectively, and can be absorbed and utilized by plants.

(3) The phosphorus containing organic compounds in the transformation compost, under the action of various saprophytic microorganisms, form phosphoric acid, which becomes a nutrient that plants can absorb and utilize.

(4) The transformation of sulfur-containing organic matter in compost generates hydrogen sulfide through the action of microorganisms. Hydrogen sulfide is prone to accumulate in anaerobic environments and can be toxic to plants and microorganisms. But under well ventilated conditions, hydrogen sulfide is oxidized into sulfuric acid by sulfur bacteria and reacts with the salt base in compost to form sulfate, which not only eliminates the toxicity of hydrogen sulfide but also becomes a sulfur nutrient that plants can absorb.

In the case of poor ventilation, reverse sulfurization occurs, causing sulfuric acid to be converted into H2S and lost, and causing toxicity to plants. During the composting fermentation process, the aeration of compost can be improved by regularly flipping it over, which can eliminate the anti sulfurization effect.

(5) The conversion of lipids and aromatic organic compounds into tannins, resins, and other structures is complex and decomposes slowly, resulting in the production of CO2 and water; Lignin is a particularly stable organic compound in compost containing plant-based materials such as bark and sawdust. It has a complex structure, contains aromatic nuclei, and exists in polymeric form in plant tissues, making it extremely difficult to decompose. Under well ventilated conditions, it is mainly decomposed slowly through the action of fungi and actinomycetes, and its aromatic nucleus can be transformed into quinone compounds, which are one of the raw materials for the synthesis of humus. Of course, these substances will continue to decompose under certain conditions.

In summary, the mineralization of organic matter in compost can provide quick acting nutrients for crops and microorganisms, provide energy for microbial activity, and prepare basic raw materials for the humification of organic matter in compost. When composting is dominated by aerobic microbial activity, organic matter quickly mineralizes to produce more carbon dioxide, water, and other nutrients, decomposing quickly and thoroughly, and releasing a large amount of heat energy; When the activity of anaerobic microorganisms is dominant, the decomposition rate of organic matter is slow and often incomplete, releasing less heat energy. The decomposition products, in addition to plant nutrients, are also prone to accumulate organic acids and reducing substances such as CH4, H2S, PH3, H2. When they reach a certain level, they are detrimental or even harmful to crop growth. Therefore, the overturning during composting fermentation is also to convert the type of microbial activity and eliminate harmful substances.