各種長期定位施肥試驗(yàn)中,評(píng)估土壤有機(jī)碳(SOC)在團(tuán)聚體的固定保存以及它的穩(wěn)定過程對(duì)于實(shí)現(xiàn)可持續(xù)農(nóng)業(yè)系統(tǒng)至關(guān)重要。本課題依托湖南南縣10年長期定位試驗(yàn),在中國南方潮土性水稻土上進(jìn)行研究,以不同紫云英用量(MV;15t,22.5t,30t和37.5t)和化肥用量(F;100%,80%和60%)做各處理搭配,旨在評(píng)估0-20cm土壤水穩(wěn)性團(tuán)聚體(WSA)及其穩(wěn)定性指數(shù);團(tuán)聚體中有機(jī)碳的密度分組(f LOC,c-i POC,f-i POC和m SOC)對(duì)于團(tuán)聚體的物理保護(hù)機(jī)制,以及土壤化學(xué)性質(zhì)和粘土礦物的變化。結(jié)果表明,與CK和F處理相比,在37.5t+F80處理(提高76.7%和10.1%)和30t+F60處理(提高80.6%和12.5%)中,土壤大團(tuán)聚體(0.25～2 mm)顯著提高(P<0.05)。在37.5t+F80處理(提高51.4%和22.7%)和30t+F60(提高54.3%和22.7%)處理下,平均重量直徑(MWD)和幾何平均直徑(GMD)顯著提高。與CK相比,22.5t+F80、37.5t+F80和30t+F60處理的土壤有機(jī)碳含量顯著增加,分別增加了31.0%、38...

【文章頁數(shù)】：101 頁

【學(xué)位級(jí)別】：碩士

【文章目錄】：
中文摘要
Abstract
List of Abbreviations
1.Introduction
    1.1.Conceptual overview of the research
        1.1.1.Global status and importance of rice production
        1.1.2.Consequences of long-term excessive use of chemical fertilizers
        1.1.3.Green manuring:Chinese milk vetch in paddy soils
        1.1.4.Soil carbon sequestration mechanisms and SOC density fractions
        1.1.5.Effects of fertilization on soil aggregation and aggregate stability
        1.1.6.Effects of fertilization on carbon sequestration and density fractions
    1.2.Clay mineralogy:Definition
        1.2.1.Role of clay minerals in soil
        1.2.2.Effects of organic and mineral fertilization on clay mineralogy
    1.3.Novelty and purpose of the study
        1.3.1 Novelty
        1.3.2.Research objectives
    1.4.Schematic overview of the study
2.Material and methods
    2.1.Experimental description and sampling
    2.2.Determination of soil aggregation
    2.3.Soil organic carbon fractionation
    2.4.SOC analysis and calculations
    2.5.Determination of soil chemical characteristics
    2.6.Separation of soil clay fraction
    2.7.Determination of elemental composition of clay fraction
    2.8.Clay mineralogical Analysis
    2.9.Statistical analysis
3.Results
    3.1.Soil chemical properties
        3.1.1.Soil p H
        3.1.2.Primary nutrient contents
        3.1.3.Relationship between soil p H and soil nutrient characteristics
    3.2.Soil aggregation and soil organic carbon
        3.2.1.Distribution and stability of water stable aggregates
        3.2.2.Distribution of SOC density fractions
        3.2.3.SOC in bulk soil,aggregates and enrichment
        3.2.4.SOC contents in density fractions
        3.2.5.Hierarchical agglomerative cluster analysis
        3.2.6.Relationship among aggregation,SOC contents,and density fractions
    3.3.Clay minerals
        3.3.1.Clay mineralogical identification
        3.3.2.Modifications in XRD patterns
        3.3.3.Relative contents of clay minerals
        3.3.4 Relationship among soil chemical properties,SOC and clay minerals
4.Discussion
    4.1.Changes in soil properties
    4.2.Soil aggregate stability and organic carbon sequestration
    4.3.Clay mineralogical modifications
5.Conclusion and future perspectives
    5.1.Conclusion
    5.2.Future perspectives
6.References
Acknowledgements



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