Cow manure, a common livestock and poultry waste, is rich in nutrients such as nitrogen, phosphorus, and potassium. Through scientific processing, it can be transformed into high-quality organic fertilizer, effectively mitigating livestock pollution while providing natural nutrients for crops. The conversion process consists of three main steps: pretreatment, fermentation, and processing, each requiring meticulous attention to detail.
The first step, pretreatment, focuses on adjusting composition and controlling moisture. Fresh cow manure has a high moisture content (approximately 70%-80%). It must be aired or supplemented with dry straw, sawdust, or other materials to reduce the moisture content to 50%-60%, ideally lumping together and disintegrating upon contact. The carbon-nitrogen ratio should be adjusted to a range of 25:1-30:1. If the nitrogen content in the manure is too high, the proportion of straw can be increased to avoid foul odors during fermentation. After pretreatment, impurities such as gravel and plastic must be removed to prevent degradation of the fertilizer's quality.
The second step is high-temperature fermentation. Microorganisms within the manure pile begin to decompose organic matter, gradually raising the temperature to 60-70°C. This temperature kills insect eggs, pathogens, and weed seeds in the manure, preventing soil contamination during subsequent fertilization. During this period, a compost turner is used to regulate the oxygen content and temperature of the manure pile to prevent local overheating or oxygen deficiency. When the manure pile changes color from brown to dark brown and the temperature drops below 40°C, high-temperature fermentation ends and the composting phase begins. Microbial activity weakens at this point, further decomposing organic matter into stable humus. The manure pile volume decreases by approximately 30%, and the original odor disappears.
The final step is processing, achieving "fineness and ease of use." Once composted, the dung can be crushed in a crusher to remove incompletely decomposed coarse fibers, then screened to create uniform particles. For long-term storage or commercial sales, a small amount of bentonite can be added as a binder. The dung can then be granulated using a granulator. After packaging, it should be stored in a cool, dry place. This completes the transformation of the dung into organic fertilizer.
From smelly cow dung to organic fertilizer that nourishes all things, this process not only realizes the resource utilization of waste, but also practices the ecological concept of "lucid waters and lush mountains are gold and silver mountains", injecting new vitality into the sustainable development of agriculture.
