畜禽养殖场粪便清扫、堆积及处理单元氮损失率研究

Nitrogen Loss During Cleaning, Storage, Compost and Anaerobic Digestion of Animal Manures in Individual Treatment Unit

畜禽粪便还田利用是规模养殖场污染治理与控制的有效措施。畜禽粪便从出舍到农田施用,其氮素会有不同程度的损失,对其定量估算有利于畜禽粪便处置或资源化过程中的氮素管理。在总结国内外已有研究报道的基础上,结合本研究室最新的研究成果,探讨了猪粪、牛粪和禽粪在清扫、堆积、高温堆肥、厌氧发酵和沼液贮存这5个单元的氮损失率,估算了畜禽粪便3条主要处理利用途径的氮素实际入田率,分别为：清扫→堆积→还田（29%~80%N,均值为55%N）;清扫→堆积→高温好氧堆肥→还田（6%~56%N,均值为31%N）;清扫→厌氧发酵→沼液贮存→还田（9%~51%N,均值为30%N）。旨在为农田负荷量估算、种养结合的农作物种植面积配置、养殖场废弃物污染风险分析及其防治技术制定等提供科学依据。

Modern livestock production systems,based on intensification in large farms,produce huge amount of manures and slurries,which must be managed under appropriate disposal practices to avoid a negative impact on the environment.Compost is increasingly considered as a good way for manure treatment with economic and environmental profits,since this process eliminates or reduces the risk in terms of pathogen,parasite and weed seed spreading associated with direct land application of manure and leads to a final stabilized product.Recently,animal wastes have been successfully employed in anaerobic biogas production,which was viewed as a pragmatic approach to rationalize energy costs in animal farms.The digested slurries application as fertilizers is increasingly considered as a good way for recycling the surplus of manure for agriculture,and much research work has been carried out in the last decade.However,after manures clean from barns,nitrogen in manures would loss to varying degrees before farm application,Nitrogen losses impact negatively on the manure composting process,by decreasing nutrient concentration,reducing compost quality,and generating health and environmental problems.Nitrogen losses through composting can occur by NH3 volatilization,leaching and denitrification.In addition,nitrogen in manures could loss during the anaerobic digestion and the storage of digested slurries.The nitrogen content in manures cannot indicate the actual amount of nitrogen entered to farmlands.In order to understand nitrogen loss rate in manures and their actual application rate to farmlands,the first part of this paper reviewed the information on nitrogen loss in units of cleaning,storage,composting,anaerobic digestion of manures in the literature.Then,the latest research results from our group such as nitrogen losses from composting and anaerobic digestion of pig,dairy and poultry manures was presented.On the basis of literature review and our investigation,three treatment routes of manures and their nitrogen inputs to farmlands were proposed,i.e.via cleaning and storage(29%~80%N input with 55%N on average),composting(6%~56%N input with 31%N on average),and anaerobic digestion(9%~51%N input with 30%N on average).Special attention should be paid to the nitrogen loss of manures in each treatment unit for providing scientific basis on the estimation of nitrogen load,allocation of planting area,evaluation of pollution risks and establishment of control criteria.