Livestock and poultry manure and straw are widely recognized in the industry as the “golden combination” of organic fertilizer raw materials. Livestock and poultry manure is rich in nitrogen, phosphorus, and potassium, and has a high organic matter content, but it has a high water content, a low carbon-to-nitrogen ratio, and poor aeration. Straw, on the other hand, has a high carbon content and a loose structure, but its nutrient release is slow. Mixing the two achieves carbon-nitrogen complementarity, moisture regulation, and porosity optimization, providing an ideal living environment for microorganisms.
Why is it a “golden combination”?
From a carbon-to-nitrogen ratio perspective, chicken manure has a C/N ratio of approximately 10:1, while straw has a C/N ratio as high as 60–80:1. The optimal C/N ratio for aerobic fermentation is 25–30:1. Mixing chicken manure and straw at a volume ratio of 3:1 to 4:1 adjusts the C/N ratio to the ideal range. In terms of moisture content, fresh chicken manure has a moisture content of 60%–80%, while straw has a moisture content of only 10%–15%. Mixing them can reduce the moisture content to the optimal fermentation range of 50%–60%. Structurally, straw provides porosity to the pile, preventing compaction and oxygen deficiency, while the manure provides nitrogen and moisture to the straw, accelerating lignin decomposition.
Core Parameters for Scientific Proportioning
Carbon-to-Nitrogen Ratio: 25–30:1, adjusted by the amount of straw. Simple estimate: 1 ton of chicken manure (dry basis) requires approximately 0.3–0.4 tons of dry straw.
Moisture Content: 50%–60%, ideally able to form a clump when squeezed in the hand, with water seeping between the fingers but not dripping.
pH Value: 6.5–8.0; add lime if too acidic, add gypsum if too alkaline.
Turning Frequency: Turn the pile every 1–2 days after the pile temperature reaches 55℃. During high-temperature periods (>65℃), turn the pile immediately to cool it down.
Supporting Equipment and Processes
In the organic fertilizer production equipment, a pulverizer is required at the front end to process straw, and a mixer ensures uniform mixing of manure and straw. For the fermentation stage, a trough-type or tracked compost turner is recommended to achieve regular oxygen supply. In the poultry manure fertilizer production process, after fermentation and maturation, uncomposted straw needs to be removed by screening before entering the granulation stage. For the chicken manure organic fertilizer production process, due to the high viscosity of chicken manure, the moisture content needs to be adjusted to 25%–35% before granulation. Disc granulation or roller extrusion granulation are both suitable. The finished granule size should be 2–4 mm, with a moisture content ≤12%.
Environmental and Economic Benefits
This combination can absorb two major non-point source pollution sources: livestock manure and agricultural straw. After fermentation, the product has an organic matter content ≥45% and nitrogen, phosphorus, and potassium content ≥5%, meeting the NY/T 525-2021 standard. Applying 200–300 kg per mu (approximately 0.16 acres) can increase soil organic matter by 0.1–0.2 percentage points and reduce chemical fertilizer use by 15%–20%. For livestock farms, turning manure into fertilizer not only alleviates environmental pressure but also creates additional revenue.
In summary, the scientific ratio of livestock manure to straw is the “first principle” of organic fertilizer production. By focusing on the three key aspects of carbon-nitrogen ratio, moisture content, and turning, and using efficient organic fertilizer production equipment, these two types of waste can be transformed into high-quality organic fertilizer, achieving a win-win situation for both ecological and economic benefits.