本文關(guān)鍵詞： 氮添加 碳循環(huán) 碳源匯 碳循環(huán)模式　出處：《內(nèi)蒙古大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著全球氮沉降、施肥活動(dòng)的增加,外源氮素添加對(duì)于碳循環(huán)的影響也逐漸成為研究熱點(diǎn)。大多數(shù)研究只關(guān)注氮素影響的某一方面,缺乏氮添加與生態(tài)系統(tǒng)關(guān)系的系統(tǒng)分析。本文通過對(duì)內(nèi)蒙古呼倫貝爾草甸草原不同水平氮添加控制實(shí)驗(yàn)中碳循環(huán)各組分的測(cè)定,分析草甸草原碳循環(huán)各個(gè)環(huán)節(jié)的特征并構(gòu)建碳循環(huán)模式,揭示N添加對(duì)于碳循環(huán)的影響以及生態(tài)系統(tǒng)碳源匯的問題。這一問題有助于深入了解全球氣候變化中外源氮增加后對(duì)該生態(tài)系統(tǒng)的影響,對(duì)以增加草甸草原生態(tài)系統(tǒng)碳匯為基礎(chǔ)的草地可持續(xù)性管理也有一定的應(yīng)用價(jià)值。主要研究結(jié)果如下：1.氮添加會(huì)顯著提高生態(tài)系統(tǒng)地上凈初級(jí)生產(chǎn)力,但對(duì)地下生產(chǎn)力的影響不顯著；2.N添加對(duì)于0-100cm土層整體及各層土壤有機(jī)碳含量均沒有顯著影響；但土壤碳的積累是一個(gè)長(zhǎng)期的過程,短時(shí)間的氮添加不能很快增加土壤有機(jī)碳的含量；3.N添加對(duì)于枯落物剩余量與分解量均沒有顯著影響,但N添加具有提高枯落物產(chǎn)量和分解量的趨勢(shì)；4.土壤呼吸對(duì)N添加濃度的響應(yīng)不同：高氮處理顯著促進(jìn)了自養(yǎng)呼吸,但卻顯著抑制了異養(yǎng)呼吸；低氮處理顯著抑制了自養(yǎng)呼吸,對(duì)于異養(yǎng)呼吸的影響并不顯著；5.土壤呼吸與土壤溫度之間關(guān)系密切,而土壤呼吸溫度敏感性對(duì)于N添加不敏感；土壤呼吸對(duì)N素添加的響應(yīng)程度與土壤濕度有關(guān),土壤濕度越大,土壤呼吸對(duì)于施肥的響應(yīng)程度越高；6.內(nèi)蒙古東部草甸草原生態(tài)系統(tǒng)在生長(zhǎng)季表現(xiàn)為凈碳匯,每年生長(zhǎng)季凈吸收130gC/m2；7.N的添加有利于草甸草原生態(tài)系統(tǒng)碳匯的增加,主要通過促進(jìn)碳吸收和減少碳排放兩種方式實(shí)現(xiàn)；高氮處理提高了凈初級(jí)生產(chǎn)力,但也促進(jìn)了生態(tài)系統(tǒng)碳排放,低氮處理對(duì)凈初級(jí)生產(chǎn)力影響較小,但減少了生態(tài)系統(tǒng)碳排放。8.構(gòu)建了草甸草原碳循環(huán)基本模式及不同N添加后的碳循環(huán)模式。
[Abstract]:With the global nitrogen deposition and the increase of fertilization activities, the effect of exogenous nitrogen addition on carbon cycle has gradually become a hot topic. Most studies only focus on one aspect of nitrogen effect. Based on the systematic analysis of the relationship between nitrogen deficiency and ecosystem, the carbon cycle components of Hulunbeir meadow in Inner Mongolia were determined in the experiment of nitrogen supplementation control at different levels. The characteristics of each link of carbon cycle in meadow grassland were analyzed and the carbon cycle model was constructed. To reveal the effects of N addition on the carbon cycle and the carbon source and sink of the ecosystem, which is helpful to understand the effects of exogenous nitrogen on the ecosystem in the global climate change. It also has some application value to the sustainable management of grassland based on increasing carbon sink of meadow grassland ecosystem. The main results are as follows: 1. Nitrogen addition can significantly improve the net primary productivity of the ecosystem above ground. But the influence on underground productivity is not significant. 2.N addition had no significant effect on soil organic carbon content in 0-100 cm soil layer. However, the accumulation of soil carbon is a long-term process, and the content of soil organic carbon can not be increased quickly by adding nitrogen for a short time. 3.N addition had no significant effect on litter residue and decomposition, but N addition had the tendency of increasing litter yield and decomposition. 4. The responses of soil respiration to N addition concentration were different: high nitrogen treatment significantly promoted autotrophic respiration, but significantly inhibited heterotrophic respiration; Low nitrogen treatment significantly inhibited autotrophic respiration, but had no significant effect on heterotrophic respiration. 5.The relationship between soil respiration and soil temperature is close, but the sensitivity of soil respiration temperature is not sensitive to N addition. The response of soil respiration to N addition was related to soil moisture. The higher the soil moisture, the higher the response of soil respiration to fertilization. 6. The grassland ecosystem in eastern Inner Mongolia shows a net carbon sink in the growing season, with a net absorption of 130 g C / m ~ (2) per year. 7.The addition of N is beneficial to the increase of carbon sink in meadow grassland ecosystem, mainly through promoting carbon absorption and reducing carbon emission. High nitrogen treatment increased net primary productivity, but also enhanced ecosystem carbon emissions, and low nitrogen treatment had little effect on net primary productivity. However, the carbon emission from ecosystem was reduced. 8. The basic model of carbon cycle in meadow steppe and the carbon cycle model after different N addition were constructed.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S812

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