What raw materials are required for organic fertilizer production?

Organic fertilizer is an essential product for improving soil quality and enhancing the quality of agricultural crops. The choice of raw materials directly determines the nutrient content, the degree of decomposition (maturation), and the production costs of the final product. The raw materials for organic fertilizer are diverse and can generally be categorized into three types: primary materials, auxiliary materials (amendments), and functional microbial inoculants. A well-balanced combination of these components is necessary to produce high-quality organic fertilizer.

Primary materials serve as the core source of nutrients and typically consist of waste products rich in organic matter. Livestock and poultry manure—such as that from chickens, cattle, sheep, or pigs—are the most common raw materials. These are readily available, rich in organic matter, and contain a balanced mix of nitrogen, phosphorus, and potassium. However, fresh manure has a high moisture content and may harbor parasite eggs or pathogens; therefore, it must undergo high-temperature decomposition (composting) to prevent issues like "root burn" (damage to plant roots) or the spread of pests and diseases. Other primary materials include agricultural waste—such as straw, peanut shells, rice husks, sugarcane bagasse, and fruit pomace—which are high in carbon and useful for adjusting the carbon-to-nitrogen (C/N) ratio of the mixture. Additionally, materials like sewage sludge, spent mushroom substrate, or cassava residue can be used, provided they are tested for heavy metals to ensure they meet the standards for organic fertilizer production.
Auxiliary materials are primarily used to adjust moisture levels and the C/N ratio, improve the aeration of the compost pile, and facilitate the fermentation process. Common examples include sawdust, wood chips, rice bran, weathered coal, and peat. Since livestock and poultry manure are high in nitrogen but lack sufficient carbon, adding materials like sawdust helps balance the C/N ratio, allowing the compost pile to heat up more quickly and ferment more thoroughly. These auxiliary materials also help reduce the overall moisture content, preventing water accumulation and foul odors, while shortening the time required for decomposition. Furthermore, because these materials are often rich in organic matter themselves, they contribute to the final organic matter content of the finished fertilizer.
Microbial inoculants (fermentation agents) are indispensable additives in organic fertilizer production. Relying solely on natural fermentation is often slow and results in incomplete decomposition. By adding specialized composting microbial strains, the temperature of the compost pile can be raised rapidly, which helps kill parasite eggs, weed seeds, and harmful microorganisms present in the manure. These inoculants also accelerate the breakdown of organic matter, reduce unpleasant odors during the fermentation process, and shorten the overall production cycle. Although only a small amount of fermentation microbial inoculant is required, it is crucial to the quality of the final product.
There are several key considerations when selecting raw materials. First, harmful substances must be strictly controlled; materials containing excessive heavy metals, significant amounts of plastic, or chemical pollutants are strictly prohibited. Second, the carbon-to-nitrogen (C:N) ratio must be managed—an ideal ratio for composting is generally around 25:1. A C:N ratio that is too high slows down fermentation, while one that is too low can lead to the release of ammonia, resulting in a loss of nutrients. Third, raw materials require pre-treatment: large items must be shredded, and materials with excessive moisture content should be air-dried to ensure a stable and efficient organic fertilizer production process.
In general, the production of organic fertilizer relies primarily on organic waste from agriculture, forestry, and livestock, supplemented by conditioning agents and fermentation microbial inoculants, all while adhering to the principle of harmless treatment. Transforming waste resources into high-quality organic fertilizer not only enables the resourceful utilization of waste but also reduces reliance on synthetic fertilizers and helps preserve soil fertility—making it a vital component in the development of circular agriculture.