Livestock and poultry manure is an ideal kind of high-efficiency bio-organic fertilizers in agricultural production process. Appropriate application of livestock manure can improve soil, cultivate soil fertility and prevent soil degradation. However, the direct application would cause environmental pollution and decline agricultural products in quality. What’s worse, for those towns, factories, schools and other surrounding areas with dense population, a large amount of manure produced by intensive and large scale livestock farm would not only cause serious pollution, but also bring disease spreading easily without proper treatment.
Hazards of Unfermented Livestock Manure
▲ Diseases and insect pests infection: the feces contain a good deal of microorganism harmful to health, like colon bacillus and threadworm, which may cause the transmission of diseases and insect pests after direct manure fertilization, make plants sick easily, pollute environment and also produce adverse effect for human health.
▲ Burning seedlings: once achieving fermentation conditions, unfermented manure in soil contains active microorganism and the heat produced during fermentation process would severely affect plant growth or produce the phenomenon of burning seedlings.
▲ Poison gas harm: manure would produce sulfur dioxide and ammonia gas that are noxious gas for crops and atmospheric environment.
▲ Oxygen-poor soil: organic matter would consume much of the oxygen from soil during the process of decomposition.
▲ Slow fertilizer efficiency: the nutrients unfermented manure are slow-release fertilizer, which cannot be absorbed and used directly by plants.
▲ Environment contamination: after all the rain and wind, fertilizer efficiency of manure would be washed away, polluting river and soil.
▲ Inconvenient transportation: livestock and poultry manure without treatment have large size and low effectiveness, which is inconvenient for transportation and practical application.
Main Factors Affecting Manure Composting
◆ Carbon-nitrogen ratio: among the various elements required by microbiological decomposition, carbon and nitrogen are the most important parts. The ratio of carbon to nitrogen is related to the temperature of composting. If carbon-nitrogen ratio is too high, too much carbon would lead to the shortage of nitrogen raw material, and the growth of bacteria and other microorganisms would be limited, then decomposition speed of organic matter would be slow, finally composting and fermentation process would be long. In the meantime, it would make the finished compost fertilizer with high carbon nitrogen ratio, which would capture Nitrogen in soil, affecting crops growth. But if the ratio is too low, especially lower than 20:1, carbon available for consumption is not enough while nitrogen nourishment is relative surplus, easy to volatilize, lowering fertilizer efficiency. In order to make balance the microbial nutrition involved in organic matter decomposition, the composting carbon-nitrogen ratio should satisfy the best value 25-35:1. It is common to use raw materials with high carbon content (like straw) to adjust the ratio of carbon and nitrogen.
◆ Moisture content: the best moisture content of manure composting is usually 50%-60%. If lower than 30%, it would have a strong impact on life activities of microorganisms; if too high, moisture would squeeze out air and reduce the composting speed, producing odor and nutrient leaching. Composting materials water content is also closely related to its ventilation capacity and structural strength. Solid liquid separator is able to adjust water content of raw materials, reducing manure moisture to a great extent.
◆ Temperature: for composting, temperature is an important factor for the smooth progress of composting and fermentation because it has a significant role in microorganisms growth. It is generally believed that the degradation efficiency of organic matter by high temperature bacteria is higher than that of medium temperature bacteria. In the early days of compost, the temperature of piles is always consistent with the nearby environment temperature; after 1-2 days medium temperature bacteria action, compost pile temperature can reach the ideal high temperature bacteria at 50-65 Celsius. Under such high temperature and with the help of suitable compost turner machine, it only needs 5-6 days for manure composting to realize harmless requirement.
◆ Ventilation for oxygen: ventilation and oxygen supply is one of key factors for successful composting, which has a connection with organic matter content in the compost materials. More organic carbon would consume more oxygen. In the composting process, the appropriate oxygen rate is 18%. Once lower than 18%, the microbial life activities in the good composting fertilizer would be limited, and the compost would easily enter the anaerobic state to produce odor.
◆ pH value: as a crucial factor affecting the growth of microorganisms, pH value should not be too high or too low, and the optimum value of the general microorganisms is neutral or weakly alkaline. In addition, the pH also affects the loss of nitrogen. Therefore, when the pH is above 7.0, nitrogen is volatilized in the form of ammonia. But do not worry, under normal circumstances, the pH of livestock manure can meet the fermentation requirements.
◆ Particle size of manure composting: increasing the surface area of raw material particles can promote the activities of microorganisms and accelerate the composting process because microorganisms move through the surface of organic particles. Livestock and poultry manure themselves are thick slurry, which usually need to add large size organic materials to increase porosity.
In a word, it is quite essential to compost livestock and poultry manure properly before using them into crops and plants. In order to make manure compost faster and better, people also need to know the main factors affecting manure composting and fermentation process. Besides, for commercial and large scale composting business, professional compost turner machine is also of the essence in virtue of its outstanding turning efficiency, accelerating composting process significantly.