1. Looseness: The biological fermentation method starts to loosen and become crumbly on the fourth day of fermentation.

2. Odor: The odor of the biological fermentation method starts to decrease from the second day, basically disappears on the fourth day, completely disappears on the fifth day, and emits the fragrance of soil on the seventh day.

3. Temperature: The biological fermentation method reaches a high temperature stage on the second day and starts to fall on the seventh day. Maintaining a high temperature stage for a long time, the fermentation is thoroughly mature.

4. PH value: The PH value of the biological fermentation method reaches 6.5.

5. Moisture content: The initial moisture content of the fermentation raw material is 55%, and the moisture content of the biological fermentation method can be reduced to 30%.

6. Ammonium nitrogen (NH4+W): At the beginning of fermentation, the content of ammonium nitrogen increases rapidly and reaches the highest amount on the fourth day. This is caused by hydrogenation and mineralization of organic nitrogen. Subsequently, the ammonium nitrogen in the organic fertilizer gradually decreases due to volatilization loss and conversion into nitrate nitrogen. When the ammonium nitrogen is less than 400mg/kg, it reaches the maturity mark. The ammonium nitrogen content can be reduced to about 215 mg/g by biological fermentation.

7. Carbon-nitrogen ratio: When the carbon-nitrogen C/Ratio of compost reaches below 20, the maturity index is reached.