本文關鍵詞：添加生物炭對秸稈還田土壤VOCs釋放和微生物多樣性影響研究　出處：《安徽師范大學》2016年碩士論文　論文類型：學位論文

  更多相關文章： 秸稈還田 揮發(fā)性有機物(VOCs) 土壤微生物多樣性 生物炭 排放通量 PCR-DGGE

【摘要】：秸稈還田是我國常用的一種秸稈處理手段,秸稈還田分解過程中會釋放大量揮發(fā)性有機污染物(VOCs)。VOCs是近地面大氣臭氧和二次有機氣溶膠的重要前體物,同時對臭氧層空洞、全球輻射平衡和氣候變化具有重要貢獻,因此很有必要尋求一種途徑來控制秸稈還田土壤VOCs排放。生物炭由于其自身的結構特性,對土壤CO_2、N2O和CH4等氣體具有顯著減排效應,而有關于生物炭添加對秸稈還田土壤VOCs減排是否可行目前還未見報道。秸稈還田分解主要是一個微生物參與的代謝過程,而生物炭施入到土壤中會對土壤微生物多樣性產(chǎn)生影響,因此研究生物炭添加對秸稈還田過程中微生物群落結構和多樣性的變化能更好地探究生物炭對秸稈還田土壤VOCs釋放的影響機理。本研究以安徽省蕪湖市的農(nóng)田土壤和小麥秸稈為對象,設置添加(SBW)和未添加(SW)生物炭秸稈還田土壤兩個處理,研究分析秸稈還田過程中VOCs的組成特征和排放通量、土壤微生物數(shù)量、細菌群落結構變化等,探討添加生物炭對秸稈還田土壤VOCs排放的影響機理。本研究的主要結論如下:(1)秸稈還田過程中釋放出來的VOCs主要包括非甲烷碳氫化合物(NMHCs)、含硫化合物(VSCs)和含氧化合物(OVOCs)三類物質(zhì)。生物炭添加顯著增加了VOCs排放量,特別是OVOCs排放量,但顯著降低了VSCs排放量。SW和SBW處理中VOCs累積排放量分別為7.29 mg kg-1和36.5 mg kg-1,其中OVOCs(酮類、醇類、醛類、酮類和酯類,共33種)排放量分別為6.95 mg kg-1和36.2 mg kg-1,占對應兩個處理中VOCs總排放量的95.3%和99.1%;NMHCs(C2-C5的5種烷烴和5種烯烴)排放量分別為211μg kg-1和256μg kg-1;VSCs包括二甲基硫醚(DMS)、二甲基二硫醚(DMDS)、二甲基三硫醚(DMTS)和二硫化碳(CS2)四種,排放量分別為132μg kg-1和81.4μg kg-1。對于單種VOCs,SW處理中丙酮排放量最高,占VOCs總累積排放量的45.3%,其次是乙醇、2-丁酮、2-戊酮、異丙醇、2-丁醇和乙醛,這7種物質(zhì)共占VOCs總排放量的91.7%;SBW處理中,丙酮也是最主要的VOC,占VOCs總排放量的38.3%,其次是2-戊酮、2-丁酮、乙醇、異丙醇、2-己酮和2-庚酮,這7種物質(zhì)共占VOCs總排放量的95.9%。(2)秸稈還田過程中,兩個處理中VOCs排放速率隨時間發(fā)生明顯變化。SW處理中10種NMHCs分別0-24天和24-56天兩個時間段內(nèi)出現(xiàn)1-2個峰值,四種VSCs基本在前30天釋放,并在12天左右達到峰值,大部分OVOCs基本在前30天釋放,并在20-30天范圍內(nèi)出現(xiàn)峰值。SBW處理中10種NMHCs一般在0-17天和24-56天兩個時間段內(nèi)出現(xiàn)1-2個峰值,DMS、DMDS和DMTS均在17天達到排放峰值,且均在前34天釋放,CS2則在4-17天和24-44天時間段內(nèi)各達到一個峰值,而OVOCs在0-24天和34-56天兩個時間段內(nèi)出現(xiàn)1-2個峰值。(3)DGGE譜圖和多樣性分析結果表明,生物炭添加增加了秸稈還田土壤細菌DGGE圖譜條帶位置和灰度值以及均勻度的變化,但兩個處理土壤細菌群落Shannon-Wiener指數(shù)和豐富度沒有顯著差異(P0.05)。聚類分析結果表明,SBW處理土壤細菌群落聚為5類,SW處理土壤細菌群落可聚為6類。DGGE條帶測序和結構分析結果表明,生物炭添加導致秸稈還田土壤中Actinobacteria和Nitrospira消失和Spirochaetes、Gemmatimonadetes、Chloroflexi和WS3出現(xiàn),以及Firmicutes和Proteobacteria所占比例升高和Acidobacteria和Bacteroides所占比例降低。(4)兩個處理中各類VOCs排放量與各微生物指標(微生物菌落信息、微生物碳量,CO_2,微生物數(shù)量)呈現(xiàn)不同程度的相關性,表明微生物活動對秸稈還田過程中VOCs釋放具有重要影響。VOCs排放量與土壤化學元素的相關性研究結果表明VOCs釋放與土壤理化性質(zhì)也有一定聯(lián)系,也間接反應了與微生物活動的關系。
[Abstract]:Straw is commonly used in China, a straw processing means, straw decomposition process will release a large amount of volatile organic compounds (VOCs).VOCs is an important precursor of ozone in the atmosphere near the ground and two secondary organic aerosol, and the hole in the ozone layer, global radiation balance and climate change has important contribution, so it is necessary to to control the straw returning soil VOCs emissions to seek a way. Biochar because of their structural characteristics, the soil CO_2, N2O and CH4 gas has significant reduction effect, and a straw biochar addition on soil VOCs emission reduction is feasible at present has not been reported. The straw decomposition is mainly a microorganism in the metabolic process, and biochar applied to the soil will affect the soil microbial diversity, so the study of biochar addition on microbial community structure in the process of straw The influence mechanism and diversity can better explore the biological carbon release in straw amended soil VOCs. In this study, Anhui city of Wuhu province farmland soil and wheat straw as the object, adding (SBW) and (SW) without the addition of biochar straw two soil treatment, analysis and study of composition characteristics and emission the fluxes of VOCs straw in the process, the quantity of soil microorganisms, bacterial community structure changes, to explore the influence of straw biochar soil VOCs emission mechanism. The main conclusions of this study are as follows: (1) release the straw in the process of VOCs mainly include non methane hydrocarbons (NMHCs), sulfur compounds (VSCs) and oxygen containing compounds (OVOCs) of three kinds of material. The biochar addition significantly increased VOCs emissions, especially OVOCs emissions, but significantly reduced the cumulative emissions of VSCs.SW and SBW VOCs in the treatment of emissions were 7.2 9 mg kg-1鍜，

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