Introduction: Redefining the Value of Waste
Against the backdrop of global urbanization and intensive agricultural development, the generation of organic waste is increasing exponentially. From urban food waste to livestock manure, from post-harvest crop residues to food processing by-products, these seemingly useless materials can become a source of environmental pollution if improperly handled; if managed correctly, they can be transformed into “black gold” that nourishes the soil and promotes crop growth. Fermentation technology is the key to achieving this magical transformation. It is not only an ancient agricultural wisdom but also a core technology in modern circular agriculture and sustainable environmental management. This article will systematically introduce how to convert various organic wastes into high-quality fertilizer resources through fermentation, clarify common misconceptions about fertilizers, and provide a practical guide for home gardening enthusiasts, small-scale farmers, and agricultural practitioners alike.
Part I: The Core of Organic Waste Fermentation – Aerobic Composting
Aerobic composting is a process that utilizes naturally occurring aerobic microorganisms, under artificially created suitable conditions, to rapidly decompose organic matter into stable, harmless, and humus-rich material. This process mimics and accelerates the natural material cycle, and its success depends on the precise control of several key elements.
Step 1: Careful Raw Material Preparation
Successful fermentation begins with proper raw material pretreatment. First, strict sorting is essential to remove non-biodegradable impurities such as plastics, metals, and glass, which cannot be decomposed by microorganisms and will contaminate the final product. Second, physical treatment of the raw materials is necessary. For coarse fibrous materials like straw, sawdust, and yard trimmings, shredding them to a size of 2-5 cm is crucial, as it greatly increases their surface area, facilitating microbial attachment and decomposition. Finally, and most importantly, adjusting the carbon-to-nitrogen ratio and moisture content of the mixture is key. The ideal carbon-to-nitrogen ratio is between 25:1 and 30:1. Common “green” materials (such as fresh kitchen waste, livestock manure) are rich in nitrogen but low in carbon, while “brown” materials (such as dry leaves, wood chips, straw) are rich in carbon. Mixing the two in proportion (e.g., 3 parts chicken manure to 1 part shredded straw) is the foundation for efficient fermentation. Simultaneously, the moisture content of the material should be adjusted to 55%-60%, with a texture that feels “forms a ball when squeezed but breaks apart easily when dropped,” providing an ideal moisture environment for microbial activity.
Step 2: Scientific Pile Construction and Management
Building a suitable pile with the mixed materials is the core step. The recommended pile dimensions are: base width of 1.5-2 meters, height of 1.2-1.5 meters, and length adjusted according to the amount of material, with the overall shape being trapezoidal or arched. This structure ensures sufficient volume inside the pile for heat retention while allowing oxygen to penetrate from the outside into the core area. To accelerate the start of fermentation, microbial inoculants (such as EM bacteria, commercial compost starters, or a small amount of mature compost) can be added.
The fermentation process typically involves three stages, requiring dynamic management:
Mesophilic Phase: Within 1-3 days of starting the compost, mesophilic microorganisms multiply rapidly, decomposing simple sugars and starches, and the pile temperature quickly rises to around 50°C. The pile should be kept loose during this phase.
Thermophilic Phase: As the temperature rises to 55-65°C, thermophilic microorganisms become dominant. This stage needs to be maintained for at least 5-7 days. It effectively kills pathogens, insect eggs, and weed seeds, which is key to the sanitization of the compost. During this period, thorough turning every 2-3 days is essential to replenish oxygen, dissipate heat, and expel harmful gases (like ammonia), preventing the pile from becoming anaerobic and producing foul odors due to lack of oxygen.
Cooling and Maturation Phase: When easily degradable organic matter is mostly consumed, the pile temperature gradually drops below 40°C, entering a maturation phase lasting 20-30 days. At this stage, microorganisms like actinomycetes begin their work, synthesizing stable humus. The pile volume significantly reduces, the color turns dark brown or black, the texture becomes loose, and it emits an earthy fragrance. Turning frequency can be reduced to once every 5-7 days.
Step 3: Accurate Determination of Maturity
Whether the fermentation product is fully mature directly affects its safety and effectiveness. Judgment criteria include: uniform dark brown appearance, loose texture without clumps, and no pungent odors like ammonia. More precise indicators include: moisture content reduced to 25%-30%, and pH stabilized in the near-neutral range of 6.5-7.5. A simple and effective biological test is the “Seed Germination Rate Test”: soak a small amount of mature material in water, filter it, and use the filtrate to water seeds that germinate easily, such as radish or pak choi. If the germination rate exceeds 80% and root growth is normal, it indicates complete maturity and no phytotoxicity.
Part II: Clarifying Concepts: Amino Acid Fertilizer vs. Organic Fertilizer
In the field of fertilizers, concepts are often confused. Amino acid fertilizers and organic fertilizers are two different products serving different agricultural goals.
Organic fertilizer, as described above, is a product made from organic waste (such as manure, straw) through fermentation and maturation. Its core value lies in adding stable organic matter and humus to the soil, improving soil physical structure (e.g., increasing porosity, water retention), fostering beneficial microbial communities, and slowly and persistently releasing nutrients over the long term. It is the “foundational building material” for constructing a healthy, vibrant soil ecosystem.
Amino acid fertilizer is typically a solution of free amino acids extracted from raw materials like animal hair or plant protein through chemical or enzymatic hydrolysis processes, often chelated with trace elements. It falls under the category of functional fertilizers or organic water-soluble fertilizers. Its mechanism of action is to allow plant leaves or roots to directly absorb small-molecule amino acids, which quickly participate in plant metabolism, promoting photosynthesis, enhancing stress resistance (e.g., cold, drought), improving fruit set rates, etc. It is more like an efficient “plant nutrient infusion” rather than a soil amendment.
Therefore, the two are not substitutes but complementary. In agricultural production, using organic fertilizer as a base fertilizer for long-term soil improvement, combined with amino acid fertilizer as a foliar spray or fertigation for rapid nutrient supplementation during critical crop growth stages, can achieve the best results of “addressing both symptoms and root causes.”
Part III: Special Focus: The Correct Use of Chicken Manure
Chicken manure is an organic resource with extremely high nutrient content, but its use must follow an iron rule: it must be fully matured before application.
The hazards of uncomposted chicken manure are significant: It carries a large number of pathogens (e.g., E. coli, nematodes) and weed seeds. Direct application can cause severe crop diseases. In the soil, uncomposted chicken manure undergoes intense secondary fermentation, generating high temperatures and large amounts of ammonia, leading to “root burn” that damages plant roots and disrupts the soil microecological balance.
Composted chicken manure, however, is a treasure: After standardized aerobic composting fermentation, the aforementioned hazards are completely eliminated. Mature chicken manure becomes a high-quality organic fertilizer with comprehensive nutrients (nitrogen, phosphorus, potassium, and various secondary and trace elements), long-lasting fertilizer efficiency, and the ability to significantly increase soil organic matter and improve aggregate structure. It is suitable for almost all types of crops and is an ideal fertilizer source for producing green and organic agricultural products.
Scaling Up Organic Fertilizer Production: From Principle to Factory
The scientific principles of organic fertilizer fermentation for small-scale composting are the foundation for large-scale industrial production. In a modern organic fertilizer factory, this process is systematized into a complete organic fertilizer production line. Efficient, large-scale organic fertilizer manufacturing employs advanced fermentation composting turning technology to optimize the aerobic decomposition process. Following complete maturation, the stabilized compost proceeds to the granulation stage, where it is shaped into a marketable product.
This final step utilizes specialized fertilizer granulator equipment. Innovations like the new type two in one organic fertilizer granulator combine mixing and pelletizing for efficiency. These granulators, whether standard models or part of a bio organic fertilizer production line that includes microbial inoculation, are central to transforming bulk compost into uniform pellets. The entire industrial workflow thus scales up the core composting principles, enabling the efficient, consistent production of high-quality organic fertilizers that support sustainable agriculture by improving soil health and recycling valuable nutrients from waste.
Conclusion
Mastering the fermentation technology for organic waste is the process of transforming waste management from a cost center to a value-creating activity. It connects environmental governance with agricultural production, shifting from a linear consumption model to a circular regeneration model. Whether it’s a small compost bin at home or a large-scale fermentation facility on a farm, the principles are the same. Through scientific methods, we can not only reduce waste and protect the environment but also produce valuable resources that nourish the land and cultivate healthy crops, contributing to sustainable agriculture and living.