Composting is the most commonly used and cost-effective fermentation method, with the following steps:

1. Raw material pretreatment

Crushing: Crush high carbon raw materials (such as straw and tree branches) into small pieces of 5-10cm, increase the contact area with microorganisms, and accelerate decomposition;

Removal of impurities: Remove foreign objects (such as plastic, glass, metal) from raw materials to avoid affecting fermentation or causing fertilizer blockage in the later stage;

Mixing: Mix high carbon and high nitrogen raw materials according to a carbon to nitrogen ratio of 25-30:1, while adjusting the moisture content to 50-60% (grabbing into a ball without dripping water). If adding fermentation agents, the agents can be diluted with water and evenly sprayed onto the raw materials (the amount of agents used should follow the product instructions, usually 1kg of agents can handle 1000kg of raw materials).

2. Construction and fermentation

Site selection: Choose a location with high terrain, good drainage, and far from water sources and residential areas (to avoid odors affecting daily life and prevent rainwater erosion);

Stacking: First, lay 10-15cm thick straw/crushed wood chips on the ground (as a breathable layer), and then pile the mixed raw materials into a trapezoidal or rectangular pile with a height of 1.2-1.5 meters, a width of 2-3 meters, and no length limit (the pile is too narrow for heat dissipation, and too wide for oxygen deficiency);

Coverage: Cover the pile with plastic film, straw, or sunshade net (keep warm in winter, protect from sun and moisture in summer, and avoid nutrient loss caused by rainwater erosion), but leave a small amount of breathable holes to prevent anaerobic conditions.

3. Pile flipping management (core steps)

Timing of flipping: ① When the temperature of the pile rises to 65-70 ℃ (to avoid killing beneficial bacteria due to excessive temperature); ② After the temperature starts to decrease (indicating local hypoxia and the need to turn over the pile to supplement oxygen); ③ Usually flipped once every 3-5 days, for a total of 3-5 flips.

Pile flipping method: Flip the outer layer of the pile (low temperature, unripe part) to the middle, and the middle (high temperature, well decomposed part) to the outer layer to ensure that the raw materials are evenly decomposed. At the same time, check the moisture content and spray clean water if it is dry.