Organic fertilizer is not naturally occurring; it is "ecological nutrients" transformed through scientific processes. Its production involves multiple meticulous steps, each crucial to the final quality.
The first step in production is raw material selection and pretreatment. Organic fertilizer raw materials come from a wide range of sources, including crop straw, livestock manure, garden branches, and kitchen waste, but not all raw materials can be used directly. Workers first remove impurities such as plastics and metals, then blend the materials according to their characteristics. Subsequently, the raw materials are processed into fine particles through crushing and chopping to increase the contact area with microorganisms, laying the foundation for subsequent fermentation.
The core step is high-temperature fermentation and decomposition. The pretreated raw materials are sent to fermentation tanks or piles, where they are periodically turned using a compost turning machine to control the pile temperature between 55℃ and 65℃. This temperature kills insect eggs, pathogens, and weed seeds in the raw materials while allowing microorganisms to efficiently decompose organic matter. The entire fermentation process takes 20 to 30 days, during which temperature and humidity must be monitored in real time to ensure good ventilation and prevent anaerobic decay.
Next comes the crucial granulation stage. The pre-treated raw materials are fed into a granulator, currently the mainstream equipment being a rotary drum granulator or an extrusion granulator. Taking a rotary drum granulator as an example, the raw materials gradually agglomerate into particles with a diameter of 2-5 mm inside the rotating drum, thanks to their own viscosity and the centrifugal force of the drum. During this process, particle size must be monitored in real time, and the drum speed and feed rate adjusted to ensure uniform particle shape and avoid particles that are too large or too small, as this directly affects subsequent drying efficiency and product quality.
Finally, there is drying, cooling, screening, and packaging. The freshly formed particles have a high moisture content and need to be sent to a drum fertilizer dryer to be dried at a low temperature of 60℃~80℃ to reduce the moisture content to below 15% to prevent mold and spoilage during storage. The dried particles are still at a high temperature and are then cooled to room temperature by a cooler to prevent clumping during subsequent packaging. After cooling, excessively fine powder and oversized particles are removed using a sieving machine to ensure uniform particle size in the finished product. The qualified particles are then weighed, bagged, and sealed, becoming organic fertilizer granules convenient for farmers to use.
This transformation from waste raw materials to high-quality organic fertilizer not only achieves resource recycling but also embodies a key force driving green agricultural development.
