污泥蚯蚓堆肥中水溶性有机物的变化及其对土壤N转化的影响研究

发布时间：2018-04-16 09:31

本文选题：蚯蚓堆肥 + 城市生活污泥　；参考：《扬州大学》2017年硕士论文

【摘要】：城市生活污泥含有丰富的营养物质,经蚯蚓处理后可以作为农用有机肥。蚯蚓堆肥过程中会产生大量的水溶性有机物(DOM),随污泥施用于土壤中会对氮素循环系统造成影响。因此对污泥蚓粪中DOM施入土壤后氮素转化的研究是至关重要的。本文用蚯蚓堆肥法处理城市生活污泥,对堆肥前后污泥中水溶性有机物的分子量分布、极性组分和光谱学的变化进行了研究。并选取污泥蚓粪DOM中的代表性单糖和氨基酸施于土壤中,探讨了培养过程中土壤理化性质、氮素指标以及土壤潜在硝化速率(PNR)的变化,并利用实时荧光定量PCR方法分析了外源有机物对土壤氨氧化菌氨单加氧酶基因(amoA)丰度的影响,进一步探讨了外源有机物对氮素转化的作用机制,为污泥的资源化再利用提供理论基础。主要结论如下:(1)极性分析、分子量分级结果表明,蚯蚓处理后污泥DOM中小于300Da的组分含量高出对照组污泥6.5%,大于8000Da的组分则少了 56.3%;疏水性组分比例高出对照组50.8%。光谱分析表明,试验组中均存在羧酸、芳香族物质等,且经蚯蚓处理后污泥的DOM中蛋白质含量及分子量降低,多糖和芳香族物质含量增加。荧光光谱显示原始污泥中含有大量蛋白质和腐殖质,经过120天降解生成色氨酸、酪氨酸、葡萄糖等物质,且处理组腐殖化程度高于对照组。污泥中DOM经蚯蚓处理后浓度更小,污泥降解速度更快。通过上述分析,选取处理污泥(蚓粪)DOM中典型物质酪氨酸、葡萄糖作为后续土壤氮素转化试验的外源添加物。(2)外源有机物添加至土壤结果表明,与无蚓粪的土壤(BK)相比,施加蚓粪能有效提升土壤肥力,降低土壤pH值,显著提高土壤电导率。酪氨酸的施加对土壤中有机氮的矿化作用产生了抑制,矿化量与酪氨酸添加量成反比;而添加葡萄糖则有促进作用,且矿化量随葡萄糖剂量的增加而增大。添加酪氨酸和葡萄糖均对土壤硝化率产生抑制,且同剂量添加的葡萄糖的抑制作用高于酪氨酸62.2%。研究表明蚓粪中DOM成分和含量对土壤矿化量和硝化率的影响均有显著性差异(P0.05),体系中有机物的添加可以减少硝酸盐淋洗损失,促进土壤对氮素的保肥作用。(3)添加外源水溶性有机物后对土壤的PNR和微生物群落中氨氧化古菌(AOA)和氨氧化细菌(AOB)的amoA基因拷贝数的分析结果显示,外源DOM可以显著抑制土壤PNR;土壤PNR与土壤矿化量有显著的正相关(P0.05),但与硝化率无显著性关系。土壤中AOA和AOB amoA基因丰度远高于对照组(CK),说明外源DOM可以显著促进土壤中AOA和AOB氨氧化过程的转录水平。添加葡萄糖的土壤AOA与AOB表现出相似的变化趋势,而添加酪氨酸的趋势则不同。酪氨酸组AOA、AOB与土壤硝化率之间均存在显著性负相关、而与酪氨酸添加量成显著性正相关,葡萄糖组仅AOB与矿化量、PNR等存在显著正相关(P0.05)。同一外源有机物的不同添加剂量对土壤PNR抑制率和amoA基因拷贝数的影响均有极显著差异(P0.01)。
[Abstract]:City sewage sludge contains abundant nutrients, after vermicomposting can be used as agricultural fertilizer. The process of vermicomposting will produce a large amount of water soluble organic matter (DOM), with the sludge applied to soil will affect the nitrogen cycle system. So the sludge vermicompost application of DOM transformation of nitrogen in soil after is very important. With the treatment of city domestic sludge earthworm composting method in this paper, the distribution of molecules before and after composting sludge of water soluble organic compounds, changes of polar components and spectroscopy were studied. And the selection of sludge vermicompost in DOM of monosaccharide and amino acid in the soil, discusses the cultivation process the physical and chemical properties of soil, soil nitrogen index and potential nitrification rate (PNR) changes, and using the real-time fluorescence quantitative PCR analysis of exogenous organic matter on soil ammonia oxidizing bacteria and ammonia monooxygenase (amoA) gene abundance The effect, to further explore the mechanism of exogenous organic matter on nitrogen transformation and provide a theoretical basis for the sludge resource reuse. The main conclusions are as follows: (1) polar analysis, the classification results of molecular weight indicated that the earthworm treatment sludge after DOM less than 300Da content higher than that of the control group is greater than 6.5% of sludge. 8000Da components less than 56.3%; the hydrophobic fraction ratio higher than that of the control group 50.8%. spectroscopic analysis showed that there were a carboxylic acid group, aromatic substances, and the protein content and molecular earthworm treatment sludge after DOM decreased, increased polysaccharide and aromatic substance content. Fluorescence spectra show that the original sludge contains a lot of protein and humus, degraded after 120 days of tryptophan, tyrosine, glucose and other substances, and the treatment group than the control group. The degree of humification of sludge in DOM after vermicomposting concentration, sludge degradation rate Faster. Through the above analysis, selection of sludge (vermicompost) typical substance tyrosine DOM, glucose as the soil nitrogen transformation test of Exogenous Additives. (2) exogenous organic matter added to soil. The results showed that the soil and vermicompost (BK) compared with applying vermicompost can effectively improve soil fertility, reduce the pH value of soil, increase soil conductivity. Tyrosine mineralization of organic nitrogen applied in soil have inhibited mineralization and tyrosine addition inversely; and adding glucose is promoted, and the increase of mineralization with glucose dose increased. Addition of tyrosine and glucose on soil nitrification inhibition rate, and inhibit the same dose of glucose added is higher than that of tyrosine 62.2%. studies showed that vermicompost DOM composition and content of soil mineralization and nitrification rate had significant difference (P0.05) system. The organic addition can reduce nitrate leaching loss of nitrogen fertilizer to promote soil effect. (3) the addition of exogenous dissolved organic matter on the soil PNR and microbial community in ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) amoA gene copy number analysis results show that exogenous DOM can significantly inhibit soil PNR; there is a significant positive correlation between soil PNR and soil mineralization amount (P0.05), but no significant relationship with the rate of nitrification in soil. AOA and AOB amoA gene abundance was much higher than that of the control group (CK), indicating that exogenous DOM can significantly promote the transcription of AOA and AOB in ammonia oxidation process of soil the soil AOA and AOB. The addition of glucose showed a similar trend, but the trend is different. Adding tyrosine tyrosine group AOA, there were significant negative correlation between AOB and soil nitrification rate, with the addition of tyrosine is positively correlated, glucose group There was a significant positive correlation between AOB and mineralization amount and PNR content (P0.05). There was a significant difference in the PNR inhibition rate and amoA gene copy number of the same organic matter in the same organic matter (P0.01).

【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S141.4;X703

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