2026/11/11
While bio-organic fertilizers may appear to be a simple combination of "organic matter + microorganisms," there is no "one-size-fits-all" set of processing parameters. The specific types of microorganisms and the physical form of the raw materials dictate the necessary production route and key control points.
Methods of incorporating microorganisms vary: some are "mixed in," while others are "coated on." Sturdier strains, such as Bacillus species, can be mixed with organic powder before granulation; as the material passes through a disc granulator, the microorganisms become embedded within the granules. In contrast, fungal spores—such as those of Trichoderma—are more sensitive to mechanical stress and heat. A common approach here is to first produce granules without the fungi, then, once cooled, spray a spore suspension onto the surface to create an outer coating.
Raw material pre-treatment logic also differs: long fibers require "cutting," while high-moisture materials require "breaking up." Fibrous materials like straw are long and tough; they must be cut into pieces a few centimeters or shorter—either before or after fermentation—to prevent the fibers from tangling and disrupting the granulation process. Livestock and poultry manure present a different challenge: high moisture leads to clumping. In this case, the priority is to break apart these clumps using specialized equipment, such as a semi-wet material crusher or a cage fertilizer crusher, rather than focusing on "cutting" the material.
The "red line" for drying temperatures varies depending on the microorganisms involved. Functional bacteria generally require that the material temperature does not exceed 45–50°C; after granulation, it is best to use natural air-drying or low-temperature fluidized-bed drying. Some processes may allow for material temperatures up to 80°C in the drying drum, but this is typically only applicable when the microbial agents are applied via surface spraying or added after the main heating phase, rather than being subjected to heat throughout the entire process.
In short, the differences in bio-organic fertilizer processing do not simply come down to whether or not the product is granulated. Instead, they depend on when the microorganisms are introduced, how the raw materials are pulverized, and whether the drying temperature is compatible with the tolerance limits of the specific microbial strains. By prioritizing the characteristics of the microorganisms and the physical state of the raw materials during process design, each type of bio-organic fertilizer can be matched with the most appropriate production route.
