秸秆对猪粪静态兼性堆肥无害化和腐熟度的影响

    Effects of maize stove on the harmlessness and maturity during the static facultative composting of pig manure

    • 摘要: 为促进猪粪静态兼性堆肥产品无害化和腐熟,通过添加玉米秸秆调控堆体物理结构特性和碳氮比,采用传统自然发酵方式进行为期90 d的静态兼性堆肥试验,分别设置纯猪粪处理(P)和秸秆调控处理(PC)研究静态兼性堆肥过程腐熟度指标、粪大肠菌群以及微生物群落结构演变特征。结果表明,秸秆调控增加了堆体孔隙率(提高19.41%),促进氧气向堆体内部扩散,增强了好氧微生物对有机质的降解,降低NH4+-N,可溶性有机氮(dissolved total nitrogen, DTN)等植物毒性物质含量,提升了堆肥腐熟度,两组处理堆肥产品种子发芽指数分别为40.84%(P)和114.60%(PC)。静态兼性堆肥经过30~40 d自然发酵后,粪大肠菌群数量达到卫生安全标准,堆体温度、NH4+-N和有机酸含量均会影响粪大肠杆菌的活性。堆体中微生物以厚壁菌门、放线菌门、变形菌门等与木质纤维素降解相关的菌门为优势菌门,堆体自上而下由好氧菌属演替为厌氧菌属,并形成好氧、兼性、厌氧的微生物分层。秸秆调控增加了堆体的好氧区域,促进和提高了猪粪静态兼性堆肥无害化和腐熟度。

       

      Abstract: Static facultative composting is one of the most widely-used, cost-effective, lightweight, and simple technologies to utilize local resources in modern agriculture. More than 60% of livestock and poultry manure (especially pig manure) can be treated using static composting. Static facultative composting can also create an aerobic environment with low porosity and limited depth of air diffusion within the heap, resulting in the low metabolic activity of microorganisms. Degradation of organic matter can be inevitably delayed, due to the long fermentation cycles, low fermentation temperatures, incomplete harmlessness, and low product maturity. Alternatively, the straw can be added to adjust the physical structure, oxygen content, and C/N ratios of the heap, in order to effectively improve the rot degree of static facultative compost products for the short rot cycle. This study aims to explore the effects of straw control on the maturity and microbial community structure of static facultative composting, especially on pathogenic bacteria. The corn straw was taken to regulate the physical structure and C/N ratio of the pile. A 90-day static facultative composting experiment was conducted using traditional natural fermentation. A systematic investigation was made to clarify the maturation index, fecal coliforms, and microbial community structure in the static facultative composting. The composting device was set as a 100 L flanged iron hoop bucket. Two treatments were set up in total. The control group was set without pig manure to label as the P treatment. The mixed compost of pig manure and corn straw was labeled as the PC treatment. The wet base mass ratio of 4:1 was selected without ventilation and heap turning. The results showed that the straw regulation increased the porosity of the compost (increased by 19.41%), and then promoted the diffusion of oxygen to the interior of the compost for the better degradation of organic matter by aerobic microorganisms. Specifically, the contents of phytotoxic substances were reduced (such as NH4+-N and DTN) to improve the compost maturity. The seed germination indexes were 40.84% (P) and 114.60% (PC), respectively, in the two groups of compost products. As such, the compost maturation was accelerated during this time. The number of fecal coliforms reached the hygienic safety standard after 30 to 40 days of natural fermentation. Furthermore, the activity of fecal coliforms depended on the temperature of the pile, NH4+-N, and organic acid content. The corn straw was added to improve the diversity of bacteria and synergistic effect. Firmicutes, Actinobacteria, Proteobacteria, and other phylum related to lignocellulosic degradation were the dominant microbial phylum in the reactor, where the aerobic, facultative, and anaerobic microbial stratification was formed from the aerobic to anaerobic bacteria from the top to the bottom. Therefore, the corn straw regulation can be expected to increase the aerobic area of the pile in the process of static composting. The harmless and mature degree can be promoted in the static composting of pig manure. The finding can provide the theoretical basis and technical standardization support for the static composting of livestock and poultry manure.

       

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