土壤管理措施可改變農(nóng)田土壤微生物多樣性和CO2排放,農(nóng)田土壤微生物通過分解和礦化主要的土壤循環(huán)元素(C、N、P和S),從而影響土壤質(zhì)量和肥力。土壤微生物還通過改變土壤呼吸與微生物對土壤有機(jī)質(zhì)的分解速率從而影響地上生態(tài)系統(tǒng)中植物生長及CO2排放。本研究依托甘肅農(nóng)業(yè)大學(xué)旱作農(nóng)業(yè)綜合實(shí)驗(yàn)站于2001年設(shè)計(jì)的長期定位試驗(yàn),選取四個處理,即傳統(tǒng)耕作(T),免耕(NT),傳統(tǒng)耕作+秸稈還田(TS)和免耕+秸稈還田(NTS),于2016、2017和2018年研究了長期不同耕作措施下豌豆播前、花期與收后農(nóng)田土壤微生物多樣性與CO2排放的變化,并從土壤理化性質(zhì)角度探討耕作措施影響土壤微生物多樣性與CO2排放的主要機(jī)制,主要研究結(jié)果如下:1.免耕秸稈還田和免耕提高了土壤微生物多樣性。在0-10cm土層下,免耕秸稈還田增加了細(xì)菌16S rRNA OTUs的數(shù)量,免耕主要增加了古菌16S rRNA OTUs和真菌ITS OTUs的數(shù)量;播前、花期和收后時10-30 cm土層下非根際土壤細(xì)菌16S rRNA和真菌ITS數(shù)量較0-10 cm土層的增幅分別為1.2-8.3%和3.5-12.5%,而根際土壤細(xì)菌和真菌...

【文章頁數(shù)】：191 頁

【學(xué)位級別】：博士

【文章目錄】：
摘要
Summary
List of Abbreviations
Introduction
Chapter 1 Literature Review
    1.1 Soil ecosystem microbial community composition
    1.2 Difference between rhizosphere and bulk soil microbial activity
    1.3 Effects of tillage practices on soil microbial diversity
    1.4 Effect of tillage practices on soil physical and chemical properties
    1.5 Factors and underlying mechanisms driving soil microbial diversity
    1.6 Factors and underlying mechanisms driving soil CO₂ emission
    1.7 Importance of conservation agriculture (CA)
    1.8 Methods employed in the identification of soil microbes
Chapter 2 Materials and Methods
    2.1 Study site description
    2.2 Design of experiment
    2.3 Research workflow
    2.4 Soil sampling
    2.5 Soil moisture and temperature
    2.6 Soil chemical analysis
    2.7 Carbon emission characteristics
        2.7.1 Soil respiration monitoring and carbon emission calculation
        2.7.2 Carbon emission efficiency calculation
    2.8 Soil DNA extraction, amplification and sequencing
    2.9 Data analysis
Chapter 3 Effect of long-term tillage practices on soil physical and chemical properties
    3.1 Effect of tillage practices on soil physical properties
        3.1.1 Effect of tillage practices on soil moisture
        3.1.2 Effect of tillage practices on soil temperature
    3.2 Effect of tillage practices on soil chemical properties
        3.2.1 Effect of tillage practices on pre-sowing stage soil chemical properties
        3.2.2 Effect of tillage practices on flowering stage soil chemical properties
        3.2.3 Effect of tillage practices on pre-harvest stage soil chemical properties
    3.3 Chapter summary
Chapter 4 Impact of different long-term tillage practices on soil archaeal, bacterial and fungal communities
    4.1 Soil microbial community diversity as affected by tillage practices
        4.1.1 Diversity of pre-sowing stage soil microbial community as affected by tillage practices
        4.1.2 Diversity of flowering stage soil microbial community as affected by tillage practices
        4.1.3 Diversity of pre-harvest stage soil microbial community as affected by tillage practices
    4.2 Venn analysis of microbial OTUs abundance as affected by tillage practices
        4.2.1 Venn analysis of pre-sowing stage microbial OTUs as affected by tillage practices
        4.2.2 Venn analysis of flowering stage microbial OTUs as affected by tillage practices
        4.2.3 Venn analysis of pre-harvest stage microbial OTUs as affected by tillage practices
    4.3 PERMANOVA and ANOSIM of microbial communities as influenced by tillage practices
    4.4 Soil microbial community taxa as affected by tillage practices
        4.4.1 Pre-sowing stage phylum level soil microbial community as affected by tillage practices
        4.4.2 Flowering stage phylum level soil microbial community as affected by tillage practices
        4.4.3 Pre-harvest stage phylum level soil microbial community as affected by tillage practices
        4.4.4 Pre-sowing stage Class and Genus level soil microbial community as affected by tillage practices
        4.4.5 Flowering stage Class and Genus level soil microbial community as affected by tillage practices
        4.4.6 Pre-harvest stage Class and Genus level soil microbial community as affected by tillage practices
    4.5 Chapter summary
Chapter 5 Effect of long-term tillage practices on soil respiration and CO₂ emission
    5.1 Effect of tillage practices on soil respiration and CO₂ emission
    5.2 Effect of tillage practices on mean soil respiration and total carbon emission and carbon emission efficiency
    5.3 Chapter summary
Chapter 6 Relationship between soil microbial diversity, soil physical and chemical properties, soil respiration, and CO₂ emission
    6.1 Mantel tests between soil microbial community composition and soil physical and chemical properties and CO₂ emission
    6.2 NMDS of soil microbial community, physical and chemical properties as affected by tillage practices
        6.2.1 NMDS of pre-sowing stage soil microbial community and chemical properties as affected by tillage practices
        6.2.2 NMDS of flowering stage soil microbial community and chemical properties as affected by tillage practices
        6.2.3 NMDS of pre-harvest stage soil microbial community and chemical properties as affected by tillage practices
        6.2.4 NMDS of flowering stage soil microbial community, soil physical properties, soil respiration and CO₂ emission as affected by different tillage practices
        6.2.5 NMDS of pre-harvest stage soil microbial community and soil physical properties as affected by tillage practices
    6.3 Pearson correlation between soil microbial diversity, tillage and stubble effect, and chemical properties
        6.3.1 Pearson correlation between pre-sowing stage soil microbial diversity, tillage and stubble effect, and chemical properties
        6.3.2 Pearson correlation between flowering stage soil microbial diversity, tillage and stubblee ffect, respiration, total CO₂ emission, physical and chemical properties
        6.3.3 Pearson correlation between pre-harvest stage soil microbial diversity, respiration, total CO₂ emission, tillage and stubble effect, physical and chemical properties
    6.4 Principal component analysis of soil microbial diversity and physical and chemical properties as affected by different tillage practices
        6.4.1 Principal component analysis of pre-sowing stage soil microbial diversity and chemical properties as affected by tillage practices
        6.4.2 Principal component analysis of flowering stage soil microbial diversity, physical and chemical properties, soil respiration and CO₂ emission as affected by tillage practices
        6.4.3 Principal component analysis of pre-harvest stage soil microbial diversity, physical and chemical properties, soil respiration and CO₂ emission as affected by tillage practices
    6.5 Chapter summary
Chapter 7 Discussion and conclusions
    7.1 Discussion
        7.1.1 Soil microbial community composition as affected by tillage practices
        7.1.2 Mechanisms underlying tillage practice effect on soil microbial community
        7.1.3 Effect of tillage practices on soil on CO₂ emission
        7.1.4 Mechanisms underlying soil microbial community effect on CO₂ emission
        7.1.5 Relationship between microbial diversity and soil chemical properties
    7.2 Conclusions
    7.3 Recommendations for future research
References
Acknowledgements
導(dǎo)師簡介
Personal Resume



本文編號：3755612