The utilization of livestock and poultry manure resources needs to bridge the 'last mile'

Livestock and poultry breeding has always been a relatively fragile industry. After years of exploration, a relatively stable and low-cost pollution prevention and control model should be formed to enable farmers to have a clear understanding and improve their ability to resist market risks. On the contrary, if the accounts for disposing of livestock and poultry manure are not calculated clearly, many small and medium-sized farmers will take chances, underestimate expenses, and misjudge market conditions, increasing the volatility of the "pig cycle". Recently, there have been many incidents of livestock and poultry manure polluting water bodies nationwide, reflecting that the disposal of such pollution is still insufficient, and the "last mile" has not been completely cleared. It is necessary to conduct in-depth on-site investigations, find blockages, and take active and effective measures to clear them. Overall, livestock and poultry manure can be divided into three stages: production, treatment, and utilization. Among them, "production" is objective, and the corresponding amount of manure can be roughly calculated based on the scale of livestock and poultry breeding according to the production and discharge coefficient. If the discharge meets the standard after "treatment", it can be compared to the operation and management of urban sewage treatment plants, which have rich means and experience. Another path is to utilize resources after "governance". From the inspection results, there are currently many loopholes that should be given special attention. Firstly, the contradiction of imbalanced planting and breeding is prominent. The planting type, soil type, terrain, and climate are important factors that affect the amount of livestock and poultry manure consumed. Often, there is insufficient planting capacity, and excessive spraying of manure cannot be effectively absorbed, resulting in serious loss and accelerating the eutrophication process of receiving water bodies. Secondly, the way of resource utilization is not scientific. Foreign countries have developed supporting facilities, where special agricultural vehicles load livestock and poultry manure and use robotic arms to spray, ensuring uniform fertilization. But in most mountainous and hilly areas of our country, the method of returning manure to the fields is dumping, even forming infiltration pits, resulting in excess fertility in some areas, while other plots do not receive nutrient supplementation and continue to rely on the use of chemical fertilizers, making the plan to replace Organic Fertilizers ineffective.  

Finally, there is insufficient estimation of the harm caused by the discharge of manure from livestock and poultry farming below a certain scale. In some traditional livestock and poultry breeding areas, there are large numbers and wide distributions of livestock and poultry below a certain scale. After direct discharge of manure, the surrounding water bodies are often polluted, and these polluted patches are pieced together to form a "spark that can start a prairie fire" situation, especially in the downstream areas where water quality is worrying. The continuous progress of livestock and poultry breeding technology in our country has put forward stricter requirements for feed and additives, which reduces the pollution of heavy metals and antibiotics in manure and improves the safety of manure resource utilization. Overall, the nitrogen and phosphorus content in livestock and poultry manure is high, and treating it as a pollutant is not in line with scientific laws. Resource utilization should be given priority. The path of balanced planting and breeding is not wrong. The contradiction lies in the fact that livestock and poultry breeding is generally arranged indoors, with relatively stable production environments and little fluctuation in the amount of manure produced. However, agricultural planting is seasonal and intermittent, especially during the rainy season, where the soil's water retention effect is poor. This asynchronous production and consumption leads to the loss of nutrients such as nitrogen and phosphorus during specific periods. Therefore, firstly, the minimum supporting planting land area should be determined based on the most unfavorable conditions, and secondly, multiple methods should be found at the planting end to improve the ability to absorb livestock and poultry manure. For example, livestock and poultry manure is a natural soilless cultivation substrate, which can be used to grow vegetables such as celery or pig forage on the water surface; Cultivate dry soil nearby, plant crops such as corn, and integrate water and fertilizer; Targeted supply of greenhouse vegetable planting base. In short, every effort should be made to expand the ability of the planting end to absorb livestock and poultry manure. Through precise allocation at appropriate regional scales, high-quality organic fertilizers should be evenly sprayed onto the fields, turning the original pollutants into nutrients in a magnificent way. We have indeed taken a detour in the disposal of livestock and poultry manure. For a long period of time, we mainly treated it as an "enemy" and later transformed it into a "friend". However, the research on this "friend" is not sufficient, and there are still many details to be improved. We need to quickly open up the "last mile" of industrialization. Especially by mixing livestock and poultry manure with straw to make fertilizer, two major pollution problems in rural areas can be eliminated in one fell swoop, and the scope of application is wide. Therefore, efforts should be made to increase technology research and promotion.