氧化亞氮(N20),甲烷(CH4)和二氧化碳(CO2)是農(nóng)田排放的主要溫室氣體(GHG)。溫室氣體從土壤到大氣的生成和釋放主要受人為活動(dòng)和自然過(guò)程的影響。耕地土壤水分狀況可能在耕作過(guò)程中隨時(shí)間波動(dòng)從而導(dǎo)致土壤性質(zhì)的變化。土壤濕度/含水量是微生物活動(dòng)的重要參數(shù)。硝化細(xì)菌需要土壤孔隙中存在氧氣。可預(yù)測(cè)的是土壤水分狀況的變化會(huì)影響碳(C)和氮(N)在土壤中的周轉(zhuǎn),從而影響溫室氣體的排放。為了了解不同水分含量(淹水和濕潤(rùn)(60%WFPS)對(duì)土壤溫室氣體的排放影響,我們進(jìn)行了幾項(xiàng)室內(nèi)培養(yǎng)實(shí)驗(yàn)。旨在為探索與土壤溫室氣體排放有關(guān)的重大科學(xué)技術(shù)問(wèn)題提供科學(xué)依據(jù)。土壤采自于湖北省咸寧市的油菜-水稻輪作的水稻土壤。風(fēng)干后的土壤用來(lái)進(jìn)行不同處理(有無(wú)DCD、肥料和有機(jī)物(秸稈)組合)的室內(nèi)培養(yǎng)實(shí)驗(yàn)。在25℃下分別進(jìn)行連續(xù)淹水,連續(xù)濕潤(rùn)和淹水-濕潤(rùn)的處理。將硅膠置于培養(yǎng)瓶的頂部空間來(lái)吸收水分,從而實(shí)現(xiàn)從淹水到濕潤(rùn)的轉(zhuǎn)化。在所有實(shí)驗(yàn)中定期采集土壤樣品來(lái)分析土壤性質(zhì)和氣體濃度。pH通過(guò)pH計(jì)測(cè)定,微生物生物量碳(MBC)和溶解性有機(jī)碳(DOC)通過(guò)總有機(jī)碳分析儀((vario TOC cube,Elementar...

【文章頁(yè)數(shù)】：101 頁(yè)

【學(xué)位級(jí)別】：碩士

【文章目錄】：
Abbreviations
Abstract
摘要
Chapter 1: Background and Literature Review
    1.1 An overview
    1.2 N₂O emissions
    1.3 CH₄ emissions
    1.4 CO₂ emissions
    1.5 Aims and objectives
Chapter 2: Material and Methods
    2.1 Materials
        2.1.1 Soil
        2.1.2 Rice straw
        2.1.3 Fertilizer and DCD
    2.2 Methods
        2.2.1 Soil analysis
        2.2.2 Analysis of gas fluxes
Chapter 3: Effect of flooding-wetting events on soil N₂O, CH₄ and CO₂emissions
    3.1 Introduction
    3.2 Materials and Methods
        3.2.1 Experimental design
        3.2.2 Statistical analysis
    3.3 Results
        3.3.1 N₂O emissions
        3.3.2 CH₄ emissions/uptake
        3.3.3 CO₂ emissions
        3.3.4 Dissolved organic carbon
        3.3.5 Soil pH
        3.3.6 Concentrations of mineral nitrogen (NH4
+-N and NO3
--N)
    3.4 Discussion
        3.4.1 N₂O emissions
        3.4.2 CH₄ emissions/uptake
        3.4.3 CO₂ emissions
    3.5 Conclusions
Chapter 4: Effects of change in water regime on soil N₂O, CH₄ and CO₂emissions following addition of DCD and N fertilizer
    4.1 Introduction
    4.2 Materials and Methods
        4.2.1 Experimental design
        4.2.2 Statistical analysis
    4.3 Results
        4.3.1 N₂O emissions
        4.3.2 CH₄ emission/uptake
        4.3.3 CO₂ emissions
        4.3.4 Concentrations of mineral nitrogen (NH4
+-N and NO3
--N)
        4.3.5 Dissolved organic carbon
        4.3.6 Microbial biomass carbon
    4.4 Discussion
        4.4.1 N₂O emissions
        4.4.2 CH₄ emission/uptake
        4.4.3 CO₂ emissions
    4.5 Conclusion
Chapter 5: Change in water regime effect on soil GHG's emissions withrice straw and fertilizer addition
    5.1 Introduction
    5.2 Material and Methods
        5.2.1 Soil
        5.2.2 Experimental design
        5.2.3 Statistical analysis
    5.3 Results
        5.3.2 N₂O emissions
        5.3.3 CH₄ emission/uptake
        5.3.4 CO₂ emissions
        5.3.5 Soil NH4
+-N and NO3
--N
        5.3.6 Dissolved organic carbon
        5.3.7 Microbial biomass carbon
    5.4 Discussion
        5.4.2 N₂O emissions
        5.4.3 CH₄ emission/uptake
        5.4.4 CO₂ emissions
    5.5 Conclusion
Chapter 6: General Discussion
    6.1 N₂O emissions
    6.2 CH₄ emissions/uptake
    6.3 CO₂ emissions
    6.4 Summary and future perspectives
References
Acknowledgements



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