The degree of compost maturity ultimately determines its quality and more importantly, the value growers place on the final product. Well-matured, high-quality compost not only returns organic matter to the soil but also promotes crop vigor, reduces reliance on chemical fertilizers, and fosters beneficial biodiversity in agricultural ecosystems. By doing so, composting helps prevent environmental degradation and supports sustainable farming practices. For these reasons, the question of how to produce high-quality compost has become a central concern for both farmers and the agricultural industry.
The Role of Microorganisms and C/N Balance
Compost production fundamentally depends on the effective decomposition and biochemical transformation carried out by microorganisms. To achieve efficient microbial activity, the raw material mix in the compost pile must provide adequate nutrients. The most critical factor is the carbon-to-nitrogen (C/N) ratio. If the pile contains too much carbon, microbial activity slows down because of nitrogen deficiency. Conversely, excess nitrogen is easily converted into ammonia, producing foul odors and nutrient losses.
Carbon is the backbone of all living organisms. It provides the structural framework of cells and serves as a vital energy source. Common carbon-rich materials used in composting include wheat straw, corn stalks, dried leaves, and sawdust. Nitrogen, on the other hand, forms the foundation of amino acids, proteins, enzymes, and nucleic acids. Typical nitrogen sources include animal manure, slaughterhouse byproducts, legume residues, kitchen waste, and food-processing scraps. Although the intrinsic C/N ratio of microbial cells is approximately 8:1, additional carbon is needed to meet the energy demand during respiration. For this reason, an initial C/N ratio between 25:1 and 30:1 is generally recommended for composting. This range provides a balance between energy supply and the structural requirements for microbial growth.
Selecting Effective Microbial Agents
Not all microorganisms perform equally well in composting systems. Since microbial activity generates heat, heat-tolerant species are essential for maintaining a healthy composting process. Thermophilic Bacillus spp. and actinomycetes are well-suited, as they withstand high temperatures while continuing to promote decomposition. Moreover, since most carbon-based composting materials are rich in cellulose and lignin, microbes capable of producing cellulases and lignin-degrading enzymes are indispensable.
Beneficial fungi such as Trichoderma spp. are particularly effective at breaking down cellulose and lignin. When used in combination with Bacillus, they accelerate decomposition and stabilize the composting process. Commercial microbial products containing both Bacillus and Trichoderma strains have been shown to significantly shorten composting time, improve the release of nutrients, and enhance compost quality.
Managing Environmental Conditions
The efficiency of composting also depends heavily on moisture and oxygen availability. Adequate aeration is necessary to sustain aerobic microbial activity, while excess water can create anaerobic conditions that hinder fermentation. Ideally, moisture content should be maintained at 55% to 60%. Timely turning of the compost pile provides oxygen, redistributes materials, and helps regulate temperature. The best time to turn is when the pile has reached its peak temperature and begins to cool. At this point, Bacillus cells often sporulate due to high heat, and turning brings cooler, oxygen-rich conditions that allow them to continue working.
Turning also allows drier surface material to mix with the moister interior, ensuring uniform decomposition. For systems where turning is not practical, installing aeration pipes at the base of the pile and supplying pressurized air is an effective alternative. This method provides oxygen directly to the microbial community, sustaining rapid fermentation without manual intervention.
Secondary Benefits of Microbial Fermentation
Beyond decomposition, microbial fermentation produces valuable secondary metabolites that benefit subsequent crop applications. For example, Bacillus and Trichoderma species can release plant growth hormones, lysozymes, and natural antibiotics during composting. These compounds not only enhance soil microbial ecology but also improve plant health, boost disease resistance, and promote growth when the compost is applied to crops or forage.
In addition, the organic acids produced by microbes—and their efficient assimilation of nitrogen—help curb undesirable nitrogen transformations. This reduces the volatilization of nitrogen as ammonia and lowers odor-causing compounds such as methylamine, hydrogen sulfide, and ammonia, resulting in a cleaner, more neighbor-friendly composting process while retaining more plant-available nitrogen in the finished product.
Practical Application and Guidance
Farmers who wish to optimize composting can choose microbial products tailored to their raw material composition and environmental conditions. Adjusting the C/N ratio at the beginning of the process, maintaining proper aeration, and inoculating with beneficial microbes are practical steps that ensure faster maturity and higher compost quality.
For more information on selecting the right microbial products for your composting system or adjusting your pile’s C/N ratio to optimal conditions, please contact the JH Biotech technical team at info@jhbiotech.com