Cow manure, as a high-quality organic raw material, can be processed into granular organic fertilizer through scientific methods. This not only solves the problem of pollution from livestock farming but also provides an efficient fertilizer source for agricultural production, achieving a circular utilization of resources by "turning waste into treasure." The production of organic fertilizer requires following a scientific process, which mainly includes four stages: pretreatment, fermentation and maturation, granulation and shaping, and post-treatment. The specific procedures are as follows.
Pre-treatment is fundamental, and the key lies in optimizing the characteristics of the raw materials. First, a solid-liquid separator is used to remove water from the cow dung, reducing the moisture content of the solid phase to 65%-70%. If the moisture content is too high, sawdust can be added to assist in dewatering. Subsequently, the raw materials are mixed in a ratio of 7:3 (cow dung to straw) to adjust the carbon-to-nitrogen ratio to 25:1-30:1. At the same time, the moisture content of the mixture should be controlled at 55%-65%, ideally to a consistency where it can be held in a ball without dripping water, creating suitable conditions for subsequent fermentation.
Fermentation and maturation are crucial, directly determining the quality of the organic fertilizer. For small and medium-sized production, windrow composting can be used, piling the mixture into long windrows and regularly turning them to provide oxygen, ensuring the temperature rises to 55-65℃ and is maintained for 3-7 days to kill insect eggs and pathogens. For large-scale production, trough composting is recommended, shortening the cycle to 15-20 days and increasing efficiency. During fermentation, the mixture is turned every 3 days, and the pH value is adjusted to 7.0-8.0 to prevent acidification. When the temperature drops below 40℃ and the material becomes dark brown and loose, the maturation is complete.
Granulation and shaping are key. The matured material needs to be crushed to a particle size of ≤5mm, and impurities are removed through a vibrating screen. Granulation can be done using a disc granulator. Disc granulation has low energy consumption and a high granulation rate. After granulation, the material is dried in a rotary kiln, controlling the temperature to ≤80℃ to reduce the moisture content to below 15%. Then, it is cooled to room temperature by a cooling machine to further improve particle hardness.
Finally, the material undergoes screening and packaging. Qualified granules are separated using a double-layer vibrating screen, while oversized or undersized materials are returned for reprocessing. The finished product must be tested for indicators such as organic matter content ≥45% and total nutrients ≥5%, and only after meeting the NY525-2021 standard can it be bagged and stored. The cow manure granular organic fertilizer produced through this process can improve soil structure, reduce reliance on chemical fertilizers, and contribute to the development of green agriculture, truly achieving a win-win situation in both ecological and economic benefits.
