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微生物菌剂对毛乌素沙地土壤和植物的影响研究

Effect of Microbial Agents on Soil and Plant in the Mu Us Desert

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【Author in Chinese】 吴苗

【Supervisor】 张宇清杨占峰

【Author's Information】 北京林业大学, 林业(专业学位), 2020, 硕士

【Abstract in Chinese】 微生物在改善土壤理化性质、增加土壤酶活性、改变土壤微生物群落结构和促进植物生长定殖等方面,扮演着重要角色。由微生物制成的菌剂目前已广泛用于农业领域,但在环境恶劣的荒漠地区,其对土壤的改良作用和应用效果并未得到充分的研究和评估。为了探究微生物菌剂对沙地土壤的改良效果,筛选出最适的微生物菌剂,本研究运用野外控制实验手段,在毛乌素沙地设计了固沙网和麦草方格(下称草方格)两种固沙措施,并分别在两种措施下进行不同微生物菌剂(无菌剂施用处理、光合固碳菌剂、固氮菌剂、解磷解钾菌剂、复合菌剂)处理,观测对比分析了微生物菌剂对土壤理化性质、土壤酶活性、微生物群落结构和植物生长状况等方面的影响。主要研究结果如下:(1)在两种固沙措施下,施用微生物菌剂后,土壤微生物氮、有效磷和有机碳含量均显著提高,其中施用光合固碳菌剂后提升效果最为显著,其次是复合菌剂,且草方格措施下的处理效果要显著高于固沙网;同时,施用微生物菌剂后,土壤酸性磷酸酶、N-乙酰-β-D-氨基葡萄糖苷酶和酚氧化酶活性显著增大,两种措施下分别平均提高了24.0%、17.1%、20.0%、22.1%和19.7%、125%、43.0%、45.3%,且草方格处理中各种酶的活性增强效果均高于固沙网。(2)两种固沙措施下,施用微生物菌剂后,土壤细菌中变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroidetes)相对丰度得到提高;施用光合固碳菌剂后对变形菌门、放线菌门和拟杆菌门的影响较大,其次是复合菌剂。施用微生物菌剂增加了土壤细菌的α-多样性,其中Shannon指数表现出先降低后增加的趋势,并且对土壤细菌群落结构也具有显著影响。(3)两种固沙措施下,施用微生物菌剂后样方内植物生长迅速,其中以施用光合固碳菌剂和复合菌剂后植物盖度和高度的增加效果最为显著,其余菌剂施用处理中植物数量较少、高度较低,其中未施用菌剂处理中植物生长状况最差,基本无植物定植生长。固沙网和草方格两种固沙措施下,草方格内的植物盖度和高度显著高于固沙网措施下。研究结果表明,在沙地土壤中施用光合固碳菌剂和复合菌剂具有良好的土壤改良作用,在起到一定的固沙效果的同时,还能够促进土壤微生物的生长繁殖,改善土壤微环境,促进植物的定植生长。采用微生物菌剂改良沙地土壤操作方便,虽然微生物菌剂固沙成本略高,但可以作为一种环境友好型土壤改良剂,与生物固沙措施结合使用,用于沙化土地的土壤改良。

【Abstract】 Microbes play an important role in improving soil physical and chemical properties,increasing soil enzyme activity,altering soil microbial community structure,as well as facilitating plant growth and establishment.Currently,microbial agents have widely applied in the agricultural field;however,they have not been extensively studied and estimated in sandy soils.To explore the effects of microbial agents on sandy soils and to screen out suitable microbial agents for soil improvement,this study conducted a control field experiment under two sand-fixing measures(sand-fixing nets and straw checkerboard barriers)with different treatments of microbial agents(sterile agent treatment,photosynthetic carbon-fixing bacteria,nitrogen-fixing bacteria,phosphate-resolving potassium-resolving bacteria,and compound bacteria)in the Mu Us Desert.Soil physical and chemical properties,Soil enzyme activity,microbial community structure,and plant growth in different treatments were observed and analyzed.The results are as follows:(1)Under two sand-fixing measures,soil microbial nitrogen,available phosphorus,and organic carbon content significantly increased by the application of microbial agents.Among them,photosynthetic carbon-fixing agents has the most significant improvement effect,followed by compound agents;and microbial agents used in straw checkerboard barriers had better effects than that in sand-fixing nets.The soil acid phosphatase,N-acetyl-β-D-glucosidase,and phenol oxidase activities had been significantly increased by the application of microbial agents,with rates of 24.0%,17.1%,20.0%,and 22.1%,respectively;and the enzymatic activities was higher in the straw checkerboard barriers than that in the sand-fixing nets.(2)The microbial agents enhanced the relative abundance of Proteobacteria,Actinobacteria,and Bacteroidetes.Owing to the application of photosynthetic carbon-fixing bacteria,the effects on Proteobacteria,Actinomycetes and Bacteroidetes were greater,followed by compound bacteria.The application of microbial inoculants increased the α-diversity of soil bacteria,of which Shannon showed a trend of decreasing first and then increasing,and also had a significant effect on the structure of soil bacterial communities.(3)By the application of the microbial agents,the plant growth was substantially improved,and the photosynthetic carbon-fixing and composite agents were the most striking agents in facilitating the growth and establishment of plants.The number of plants in the microbial agents treatments was small and the height was low.Among them,the plant growth status was worst in the non-microbial agents treatment,and there was almost no plant colonization and growth.Under the two sand fixation measures of sand fixing nets and straw checkerboard barriers,the coverage and height of plants in the straw checkerboard barriers higher than that under the sand fixing nets.Our results show that the application of photosynthetic carbon-fixing bacterial agents and compound bacterial agents have better effects on soil improvement.The microbial agents not only can fix sand,but also can promote the growth and establishment of soil microorganisms,improve the soil microenvironment,and facilitate the plant growth.Although higher costs,the microbial agents,as novel environmentally friendly materials,can be used to control desertification in desert areas.

  • 【CLC code】S714.6
  • 【Downloads】147
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