畜禽粪便堆肥过程中碳氮损失及温室气体排放综述

堆肥是畜禽粪便资源化利用的重要技术，但堆肥过程中碳氮损失会降低产品的农用价值并造成温室气体排放。堆肥过程中的污染气体排放受多种因素影响，本文综述了堆肥原料类型、辅料类型、初始C/N、含水率和通风速率对畜禽粪便堆肥过程碳氮损失和温室气体（CH₄、NH₃、N₂O）排放的影响。结果发现：48.7%的C和27.7%的N在堆肥过程中损失，其中CH₄-C损失平均占初始总碳的0.5%，NH₃-N和N₂O-N损失分别占初始总氮的18.9%和1.1%。不同种类粪便堆肥碳氮损失差异明显，猪粪和鸡粪堆肥的温室气体排放量高于牛粪和羊粪。选择富含C的辅料与畜禽粪便联合堆肥均可促进有机物降解，其中以稻草或锯末为辅料时的温室气体排放量较低。初始C/N对堆肥过程N损失影响较大，总氮、NH₃和N₂O的损失均随C/N的增加而降低，其中C/N为20~25时最适宜N素保留。初始含水率显著影响CH₄和N₂O的排放，其排放量随含水率的增加呈显著上升趋势，以含水率为60%~65%最为适宜。通风速率（以堆肥干基计）为0.1~0.2 L·kg^-1·min^-1时，CH₄排放和总碳损失较低；通风速率为0.1~0.3 L·kg^-1·min^-1时，N₂O、NH₃和总氮损失较低。因此，为降低畜禽粪便堆肥过程碳氮损失和温室气体排放量，建议采用的工艺参数为：通风速率0.1~0.3 L·kg^-1·min^-1、含水率60%~65%、C/N为20~25。

A review of carbon and nitrogen losses and greenhouse gas emissions during livestock manure composting

Composting is an important technology for including animal manure in resource utilization. At present, emitted gasses and carbon and nitrogen losses during composting can reduce compost''s agricultural value and exacerbate the atmospheric greenhouse effect. The composting process is affected by several factors. This article summarized types of raw materials, auxiliary materials, initial C/N, initial moisture content, ventilation rate of greenhouse gas(CH₄, NH₃, N₂O)emissions, and carbon and nitrogen losses. Nearly half(48.7%)of initial C and one-third(27.7%)of initial N content were lost during composting under current management practices. Average loss of carbon in the form of CH₄ accounted for 0.5% of the initial TC, and loss of nitrogen in NH₃ and N₂O forms accounted for 18.9% and 1.1% of initial TN, respectively. Composting with different raw materials significantly altered these parameters. The greenhouse gas emissions of pig and chicken manure compost were higher than those of cow and sheep manure composts. Choosing C-rich auxiliary materials, and composting with livestock and poultry manure could promote organic matter degradation. Among the potential auxiliary materials, when straw or sawdust was used, greenhouse gas emissions were lower. The C/N ratio greatly influenced N loss, and overall loss of NH 3, N₂O, and TN decreased with increasing C/N. C/N ratios between 20 and 25 were most suitable for retention of N. Initial moisture content significantly affected CH₄ and N₂O emissions, with emissions increasing significantly with increasing moisture content. Overall, the most suitable moisture content was 60%~65%. A ventilation rate(based on dry matter)of 0.1~0.2 L·kg^-1·min^-1 reduced relative CH₄ emissions and TC loss. A ventilation rate of 0.1~0.3 L·kg^-1·min^-1 reduced relative N₂O, NH₃ and TN losses. Therefore, to reduce carbon and nitrogen losses and greenhouse gas emissions during composting, the recommended process parameters are as follows:ventilation rate 0.1~0.3 L·kg^-1·min^-1, moisture content of 60%~65%, and C/N ratio of 20~25.