双氰胺对农业废物堆肥过程及反硝化功能基因的影响研究

发布时间：2018-08-14 14:14

【摘要】：堆肥是有效处理农业废物的生物技术之一,通过堆肥技术将稻草秸秆制成有机肥是解决秸秆过剩的有效手段。堆肥过程中的氮素损失及其控制受到了国内外越来越多学者的关注,反硝化作用是造成堆肥化过程氮素损失的重要原因之一。堆肥添加剂常被用于控制堆肥过程氮素损失。多数国内外关于堆肥过程中控制氮素损失研究多关注其效果,但是较少涉及控制措施所导致的堆肥过程中氮素转化微生物的动态变化,因此揭示堆肥过程中氮素转化微生物学机理对开发新型高效堆肥保氮技术具有重要的指导作用。硝化抑制剂是一类化合物,因其对氮素转化的调节作用被广泛应用到土壤中用以提高氮肥的利用效率。近年来有学者研究在堆肥中添加硝化抑制剂作为调节氮素转化、减少氮素损失的措施,但关于硝化抑制剂对堆肥系统中反硝化微生物的影响还没有得到深入的研究。本试验以秸秆等农业废物为主要原料,添加硝化抑制剂双氰胺(Dicyandiamide,DCD)进行静态好氧堆肥试验,设置相同堆肥条件不添加DCD作为空白对照,分析了堆肥过程中各个时期不同处理的p H值、NH+4-N浓度、NO-3-N浓度和水溶性有机碳(WSC)理化参数的变化趋势,并应用实时定量聚合酶链式反应(real-time q PCR)技术对参与反硝化过程的功能基因(nir K、nir S和nos Z)丰度随时间的变化情况进行了研究。结果表明,添加DCD明显地改变了堆肥过程的氮素转化,两组堆肥样品的pH值、NH_4~+-N浓度、NO_3~--N浓度有显著差异(p0.001),WSC的降解过程受DCD的影响较小。nir K基因对DCD的响应最显著,DCD处理组的nir K基因丰度在整个堆肥过程中都维持在较低的水平,明显低于对照组。两组堆肥样品的nir S和nos Z基因在不同的时期达到峰值,且随时间变化明显。通过冗余分析得出DCD是影响nir K基因丰度的显著因子,WSC和NO-3 N浓度对反硝化基因丰度有着显著的影响(p0.05)。两组堆肥样品性质的差异是造成反硝化功能基因nir S和nos Z丰度变化的一个重要原因。
[Abstract]:Composting is one of the biotechnologies for the effective treatment of agricultural waste. Composting straw into organic manure is an effective way to solve the straw surplus. More and more scholars at home and abroad pay attention to nitrogen loss and its control in composting process. Denitrification is one of the important reasons for nitrogen loss in composting process. Composting additives are often used to control nitrogen loss during composting. Most of the studies on nitrogen loss control in composting process have focused on its effect, but less on the dynamic changes of nitrogen transformation microorganisms in composting process caused by control measures. Therefore, revealing the microbiological mechanism of nitrogen transformation in composting process plays an important role in the development of new and efficient composting technology for nitrogen conservation. Nitrification inhibitors are a class of compounds, which are widely used in soil to improve the utilization efficiency of nitrogen because of their regulation of nitrogen conversion. In recent years, some scholars have studied the addition of nitrification inhibitors in compost as a measure to regulate nitrogen conversion and reduce nitrogen loss. However, the effect of nitrification inhibitors on denitrification microorganisms in compost system has not been deeply studied. The static aerobic composting experiment was carried out by adding dicyandiamide (Dicyandiamide DCD), a nitrification inhibitor, using straw and other agricultural wastes as the main raw materials. The same composting conditions were not added with DCD as the blank control. The changing trend of pH value and NH _ 4-N concentration and the physicochemical parameters of water-soluble organic carbon (WSC) during composting were analyzed. Real-time quantitative polymerase chain reaction (real-time q PCR) was used to study the changes of nir Kir S and nos Z) abundance over time. The results showed that the addition of DCD significantly changed the nitrogen conversion during composting. The pH value of the two groups of compost samples was significantly different (p0.001) the degradation process of the DCD was less affected by the response of the DCD gene to DCD. The abundance of nir K gene in the DCD-treated group was maintained at a lower level during the whole composting process. Significantly lower than the control group. The nir S and nos Z genes of the two groups of compost samples reached the peak at different periods and changed obviously with time. The results of redundancy analysis showed that DCD was a significant factor affecting the abundance of nir K gene. WSC and NO-3 N concentration had significant effects on denitrification gene abundance (p0.05). The difference of properties between the two groups of compost samples is an important reason for the variation of the denitrification function genes nir S and nos Z abundance.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S141.4;X71

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