本文關(guān)鍵詞：氮添加對(duì)若爾蓋高寒泥炭濕地土壤碳穩(wěn)定性的影響　出處：《北京林業(yè)大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 濕地土壤 氮添加 有機(jī)碳 溫室氣體通量 微生物群落結(jié)構(gòu) 酶活性

【摘要】：我國(guó)已成為全球第三大氮沉降區(qū)。土壤有機(jī)碳庫(kù)在全球碳循環(huán)中具有重要作用,氮沉降增加會(huì)影響土壤中碳的穩(wěn)定性。本研究通過(guò)模擬氮沉降,運(yùn)用靜態(tài)箱-氣相色譜法分析不同施氮水平(0、10、20和80 kgN · hm-2 · a-1)對(duì)高寒濕地土壤碳輸入和輸出的影響,運(yùn)用室內(nèi)培養(yǎng)法研究氮添加對(duì)高寒泥炭土壤碳礦化的影響,并從微生物群落結(jié)構(gòu)和功能角度,闡述和解釋高寒濕地土壤有機(jī)碳穩(wěn)定性對(duì)氮添加的響應(yīng)機(jī)制,為濕地土壤對(duì)全球氣侯變化的貢獻(xiàn)提供參考。研究結(jié)果如下：氮添加顯著促進(jìn)了地上生物量和凋落物分解率。高氮、中氮和低氮處理下的地上生物量均值分別比對(duì)照高76.21%、56.67%和35.93%,凋落物分解率分別比對(duì)照高115.96%、90.64%和66.60%。在20℃培養(yǎng)溫度下,高氮和中氮處理下的土壤碳礦化速率顯著高出對(duì)照處理的165.79%和168.42%,低氮處理下的碳礦化速率高出對(duì)照68.42%,差異不顯著。氮添加對(duì)土壤CO2、CH4的排放具有顯著促進(jìn)作用。在高氮、中氮和低氮處理中,土壤CO2平均排放通量比對(duì)照處理高34.00%、80.96%和26.72%,土壤CH4平均排放通量比對(duì)照處理高117.65%、123.53%和62.75%。氮添加對(duì)濕地土壤碳匯產(chǎn)生了顯著促進(jìn)作用。低氮、中氮和高氮處理下的土壤碳匯量顯著高出對(duì)照處理的45.67%、34.73%和118.55%。氮添加明顯改變了土壤細(xì)菌、古生菌豐度及微生物群落多樣性。細(xì)菌豐度隨施氮量的增加而顯著增加；低氮處理下的土壤古生菌豐度明顯比對(duì)照高34.36%,高氮處理下的古生菌豐度卻顯著低于對(duì)照61.35%。凋落物殘留率與放線菌呈顯著負(fù)相關(guān),與硝化螺菌呈顯著正相關(guān)；土壤CO2排放通量與變形菌和放線菌呈顯著正相關(guān),土壤CH4排放通量與古生菌、疣微菌和浮霉菌呈顯著正相關(guān)。土壤中脲酶和硝酸還原酶活性隨施氮量的增加而顯著增加,土壤p-葡萄糖苷酶和多酚氧化酶活性均在中氮處理下最高,氮添加對(duì)過(guò)氧化氫酶活性的影響不顯著。凋落物殘留率與土壤硝酸還原酶和多酚氧化酶活性呈顯著正相關(guān)；土壤CO2排放與土壤脲酶和過(guò)氧化氫酶活性呈顯著正相關(guān),土壤CH4排放與p-葡萄糖苷酶、硝酸還原酶和過(guò)氧化氫酶活性之間存在顯著正相關(guān)�？傊�,氮添加促進(jìn)了高寒濕地土壤中的碳輸入和碳輸出,活躍了土壤中的碳動(dòng)態(tài),整體上表現(xiàn)為“氮促碳匯”
[Abstract]:China has become the third largest nitrogen deposition area in the world. Soil organic carbon pool plays an important role in the global carbon cycle. The increase of nitrogen deposition will affect the stability of soil carbon. The effects of different nitrogen levels on soil carbon input and output in alpine wetland were analyzed by static box-gas chromatography. The effects of nitrogen addition on carbon mineralization in alpine peat soil were studied by means of indoor culture, and the response mechanism of soil organic carbon stability to nitrogen addition in alpine wetland was explained from the point of view of microbial community structure and function. The results are as follows: nitrogen addition significantly promoted aboveground biomass and litter decomposition rate. The mean aboveground biomass of medium and low nitrogen treatments was 76.21% and 35.93% higher than that of the control, respectively, and the litter decomposition rate was 115.96% higher than that of the control. At 20 鈩，

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