氮沉降、生物炭对不同经营方式毛竹林土壤微生物的影响

发布时间：2019-06-10 23:48

【摘要】：土壤微生物在生物地球化学循环中起着关键作用。氮沉降、生物炭及经营方式会影响土壤微生物的数量和多样性,进而影响土壤的物质循环和能量流动。因此,本文利用高通量技术研究了不同梯度的生物炭(0 t ha~(-1),BC0,20 t ha~(-1),BC20和40 t ha~(-1),BC40)和氮沉降(0,30,60和90 kg N ha~(-1 )yr~(-1))对不同经营方式毛竹林土壤微生物生物量和多样性的影响。主要研究结果:(1)与粗放经营相比,集约经营方式下毛竹林的土壤微生物生物量碳和微生物多样性显著降低。集约经营下的Actinobacteria和Proteobacteria的相对丰度显著高于粗放经营。(2)氮沉降增加了土壤微生物生物量碳(MBC),降低了土壤微生物多样性,改变了土壤细菌结构。毛竹林的MBC随着氮沉降的增加呈现先增加后减少的趋势。高氮处理(N90)显著降低了土壤微生物多样性(P0.05),增加了Proteobacteria和Crenarchaeota相对丰度,降低了Acidobacteria和Verrucomicrobia相对丰度。(3)BC20显著增加了MBC和土壤微生物多样性(P0.05),而BC40显著降低了MBC,但对土壤微生物多样性没有显著影响。(4)添加生物炭降低了氮沉降对毛竹林土壤MBC的积极作用,缓解了氮沉降对土壤细菌多样性的消极作用。与未施加生物炭相比,BC20与氮沉降复合作用的MBC降低了6.9%-25.7%,多样性增加了5.9%-9.7%。(5)土壤微生物群落变化与土壤理化性质密切相关。毛竹林土壤MBC与土壤p H显著相关,而微生物多样性与土壤全氮(TN)、碳氮比以及NO_3~-显著相关。毛竹林土壤细菌群落主要受土壤p H和NO_3~-等的影响。研究结果表明集约经营和适量的氮沉降增加了土壤微生物生物量,降低了多样性,生物炭的添加改变了土壤微生物生物量和多样性,缓解了氮沉降对毛竹林土壤微生物生物量的积极作用和多样性的消极作用,从而为全面认识毛竹林土壤生态系统对氮沉降、生物炭及经营方式的响应提供了重要参考。
[Abstract]:Soil microorganisms play a key role in biogeochemical cycle. Nitrogen deposition, biochar and management mode will affect the number and diversity of soil microorganisms, and then affect the material cycle and energy flow of soil. Therefore, the biochar with different gradients (0 t ha~ (- 1), BC0,20 t ha~ (- 1), BC20 and 40 t ha~ (- 1) have been studied by high throughput technique. Effects of BC40) and nitrogen deposition (0, 30, 60 and 90 kg N ha~ (- 1) yr~ (- 1) on soil microbial biomass and diversity of Phyllostachys pubescens forest. The main results are as follows: (1) compared with extensive management, soil microbial biomass carbon and microbial diversity of Phyllostachys pubescens forest decreased significantly under intensive management. The relative abundance of Actinobacteria and Proteobacteria under intensive management was significantly higher than that under extensive management. (2) nitrogen deposition increased soil microbial biomass carbon (MBC), decreased soil microbial diversity and changed soil bacterial structure. The MBC of Phyllostachys pubescens forest increased at first and then decreased with the increase of nitrogen deposition. High nitrogen treatment (N90) significantly decreased soil microbial diversity (P 0.05), increased the relative abundance of Proteobacteria and Crenarchaeota, and decreased the relative abundance of Acidobacteria and Verrucomicrobia. (3) BC20 significantly increased MBC and soil microbial diversity (P 0.05). BC40 significantly decreased MBC, but had no significant effect on soil microbial diversity. (4) adding biochar decreased the positive effect of nitrogen deposition on soil MBC of Phyllostachys pubescens forest and alleviated the negative effect of nitrogen deposition on soil bacterial diversity. Compared with those without biochar, the MBC of BC20 combined with nitrogen deposition decreased by 6.9% and 25.7%, and the diversity increased by 5.9% and 9.7%. (5) the change of soil microbial community was closely related to soil physical and chemical properties. Soil MBC in Phyllostachys pubescens forest was significantly correlated with soil pH, while microbial diversity was significantly correlated with soil total nitrogen (TN), C / N ratio and NO_3~-. The soil bacterial community of Phyllostachys pubescens forest was mainly affected by soil pH and NO_3~-. The results showed that intensive management and proper nitrogen deposition increased soil microbial biomass and decreased diversity, and the addition of biochar changed soil microbial biomass and diversity. The positive effect of nitrogen deposition on soil microbial biomass and the negative effect of diversity on soil microbial biomass of Phyllostachys pubescens forest were alleviated, which provided an important reference for understanding the response of soil ecosystem of Phyllostachys pubescens forest to nitrogen deposition, biochar and management mode.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714.3

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