施氮量对土壤微生物群落组成特征的影响研究

发布时间：2018-08-07 14:03

【摘要】：连续不合理施肥措施可能破坏土壤物理结构和降低土壤微生物活性和丰富度,进而导致土壤肥力减弱。在农业生态体系中,土壤微生物是土壤生物肥力的核心,在农业物质循环中扮演重要角色。本论文以连续6年不同氮肥用量处理的黑土、冲积土和风砂土为研究对象,利用荧光酶检测、磷脂脂肪酸分析(PLFA)、Biolog-ECO微平板、Illumina Mi Seq测序、实时定量-PCR和末端限制性片段分析(T-RFLP)等现代分子生态学研究方法相互佐证,在不同层面上对土壤微生物进行系统分析。通过三种土壤微生物群落结构、碳源利用能力和氨氧化过程的研究,探讨不同施氮量下三种肥力土壤的微生物学驱动机制以及与土壤微生态环境之间的关系,对倡导合理施肥与土壤养分平衡管理、实现养分高效转化分配和农田可持续发展具有实践意义。本文主要结果如下:1. 不同施肥处理显著影响了三种类型土壤中微生物量碳氮和酶活性。低氮(168 kg/ha)处理增加了黑土和冲积土的微生物量碳(SMB-C)含量,高氮(312 kg/ha)处理增加了风砂土中SMB-C和SMB-N含量;β-葡糖苷酶、脲酶和过氧化物酶活性表现为黑土冲积土风砂土;施氮处理显著增加了三种土壤的脲酶(除风砂土312 Kg/ha)和风砂土的过氧化物酶;显著抑制了冲积土的β-葡糖苷酶,风砂土的大部分酶活性受到抑制作用(除了风砂土270 Kg/ha)。2.不同施肥处理使三种类型土壤的微生物群落结构和代谢功能呈现不同差异。施氮处理显著降低了黑土和风砂土的PLFA总量、细菌、真菌、革兰阳性菌/革兰氏阴性菌(G~+/G~-)和放线菌含量,显著增加了冲积土各菌群(除真菌外)脂肪酸含量;冲积土中微生物群落组成也显著不同于其他两种土壤,且随着施氮量增多黑土和风砂土的微生物群落组成差异逐渐减小;高氮(312 kg/ha)处理显著降低了三种土壤的微生物对碳源利用能力。3.不同施肥处理改变了三种土壤细菌微生物群落结构。三种土壤OTUs约占土壤中细菌的94.5%-98.4%,所有施肥处理中优势菌群类似,主要为变形菌门、酸杆菌门和放线菌门,约占总OTUs的75%-87%;在门(纲)水平上,酸杆菌门和α-变形菌相对丰度为:黑土冲积土≈风砂土,芽单胞菌门相对丰度为:冲积土黑土风砂土,施氮处理降低了奇古菌门和硝化螺旋菌门相对丰度;高氮(312 kg/ha)与低氮(168 kg/ha)处理相比,变形菌门、放线菌门、芽单胞菌门和绿弯菌门的相对丰度增加,酸杆菌门、拟杆菌门和奇古菌门的相对丰度降低;Beta多样性分析表明,不施肥处理和低氮(168 kg/ha)处理与高氮(312 kg/ha)处理的微生物群落组成明显分开;冗余分析表明土壤p H、有机碳、总氮和速效N是影响细菌微生物群落组成的重要因素。4.不同施肥处理改变了三种类型土壤的硝化潜势能力、氨氧化微生物的丰度和群落结构。施氮处理提高了冲积土和黑土的硝化潜势(PNA)能力,显著降低了风砂土的PNA能力;三种土壤中氨氧化古菌(AOA)丰度均高于氨氧化细菌(AOB),但随着施氮量增多,风砂土中AOA和AOB的丰度降低,黑土中AOB丰度的升高,而冲积土没有明显变化;通过T-RFLP分析表明AOA群落结构比AOB更易受不同施氮量的影响,尤其是风砂土,随着施氮量增多,AOA的群落组成多样性显著降低;冗余分析表明AOA群落结构与土壤p H、TN、NH_4~+-N和NO_3~--N和土壤硝化潜势显著相关。
[Abstract]:Continuous and irrational fertilization measures may destroy soil physical structure and reduce soil microbial activity and richness, and then lead to the weakening of soil fertility. In the agro ecosystem, soil microorganism is the core of soil biological fertility and plays an important role in the circulation of agricultural materials. This paper is dealt with in 6 years of nitrogen fertilizer treatment in a continuous period. Soil, alluvial soil and aeolian sandy soil were studied by using fluorophore detection, phospholipid fatty acid analysis (PLFA), Biolog-ECO microplate, Illumina Mi Seq sequencing, real-time quantitative -PCR and terminal restrictive fragment analysis (T-RFLP) and other modern molecular ecology research methods, and the soil microorganism was systematically analyzed at different levels. Three kinds of soil microbial community structure, carbon source utilization ability and ammonia oxidation process are studied. The microbiology driving mechanism of three fertilizer soils under different nitrogen application and the relationship with soil microecological environment are discussed. The management of rational fertilization and soil nutrient balance, the efficient transformation and distribution of nutrients and sustainable development of farmland are realized. The main results of this paper are as follows: 1. the microbial biomass carbon and nitrogen and enzyme activity in three types of soil were significantly affected by different fertilization treatments. Low nitrogen (168 kg/ha) treatment increased the microbial biomass carbon (SMB-C) content of black soil and alluvial soil, high nitrogen (312 kg/ha) treatment increased the content of SMB-C and SMB-N in the sandy soil; beta glucosidase, urea The activity of enzyme and peroxidase was in the black soil alluvial soil wind sand; nitrogen treatment significantly increased the urease of three kinds of soil (312 Kg/ha except wind sand) and peroxidase in the sand soil; it significantly inhibited the beta glucosidase in alluvial soil, and most of the enzyme activity in the aeolian sandy soil was inhibited (except for the wind sand soil 270 Kg/ha).2. different fertilizer application. The microbial community structure and metabolic function of the three types of soil showed different differences. Nitrogen treatment significantly reduced the total amount of PLFA in black soil and sandy soil, bacteria, fungi, Gram-positive bacteria / Gram-negative bacteria (G~+/G~-) and actinomycetes, which significantly increased the content of fatty acids in alluvial soils (except fungi); in alluvial soil, the content of fatty acids was significantly increased. The composition of the species was significantly different from the other two soils, and the microbial community composition of the black soil and the sandy soil decreased with the increase of nitrogen application, and the high nitrogen (312 kg/ha) treatment significantly reduced the utilization ability of three soil microorganisms to carbon source and changed the microbial microbial community structure of three soil bacteria by different fertilizer treatments. Three kinds of soil were changed. The soil OTUs accounts for the 94.5%-98.4% of the bacteria in the soil. In all the treatments, the dominant bacteria are similar, mainly deformable fungi, acid bacilli and actinomycetes, accounting for the 75%-87% of total OTUs; at the level of the gate, the relative abundance of acid bacilli and alpha deformia is: the black soil alluvial soil, the relative abundance of the alluvial soil is the alluvial soil wind The relative abundances of the gates and nitrifying spiracia were reduced in the sand, and the relative abundance of the Proteus doors, actinomycetes, buds and greenbers, the relative abundances of Actinobacteria, Pseudomonas and the Archaea gates were decreased compared with the treatment of low nitrogen (168 kg/ha), and the Beta diversity analysis showed that no fertilizer was applied to the soil of the high nitrogen (312 kg/ha) and low nitrogen (168). Treatment and low nitrogen (168 kg/ha) treatment and high nitrogen (312 kg/ha) treatment of microbial community composition distinctly, redundant analysis showed that soil P H, organic carbon, total nitrogen and quick acting N were important factors affecting the microbial community composition.4. different fertilization treatments changed the nitrification potential of three types of soil, the abundances of ammonia oxidizing microorganisms Nitrogen treatment improved the nitrification potential (PNA) ability of alluvial soil and black soil, significantly reduced the PNA capacity of sand soil, and the abundance of ammonia oxidizing archaea (AOA) in three soils was higher than that of ammonia oxidizing bacteria (AOB), but with the increase of nitrogen application, the abundance of AOA and AOB in the sandy soil decreased, and the abundance of AOB in the black soil increased, while the alluvial soil was not in the alluvial soil. The T-RFLP analysis showed that the AOA community structure was more susceptible to different nitrogen application than AOB, especially in the wind sand soil, with the increase of nitrogen application, the community composition diversity of AOA decreased significantly, and the redundancy analysis showed that the AOA community structure was significantly related to the soil P H, TN, NH_4~+-N and NO_3~--N and soil nitrification potential.
【学位授予单位】：吉林农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S154.3

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