本文選題：樟樹(shù)　切入點(diǎn)：濕地松　出處：《中南林業(yè)科技大學(xué)》2015年碩士論文

【摘要】：上個(gè)世紀(jì)以來(lái),全球范圍內(nèi)人類活動(dòng)引發(fā)的陸地生態(tài)系統(tǒng)的氮輸入增加了3-5倍,這一趨勢(shì)仍在繼續(xù)。中國(guó)亞熱帶地區(qū)已成為全球高氮沉降區(qū)之一,高氮輸入對(duì)森林生態(tài)系統(tǒng)土壤呼吸等碳循環(huán)過(guò)程和生物生產(chǎn)力變化機(jī)制影響巨大。本研究以湖南省植物園的樟樹(shù)林、濕地松林為研究對(duì)象,通過(guò)人工模擬氮沉降試驗(yàn),設(shè)置對(duì)照(CK,0 kgN·hm-1·a-1)、低氮(LN,50 kgN·hm-2·a-1)、中氮(MN,150kgN·hn-1·a-1)、高氮(HN,300kgN·hm-1·a-1)4種模擬氮沉降水平,分析了樟樹(shù)林、濕地松林土壤呼吸及其控制因素對(duì)模擬氮沉降處理的響應(yīng)。主要結(jié)果如下：(1)4種模擬氮沉降濃度處理方式對(duì)樟樹(shù)林、濕地松林土壤呼吸值日變化產(chǎn)生影響。樟樹(shù)林樣地在CK.LN.MN水平土壤呼吸最高值出現(xiàn)在晚上(22：00-4：00),最低值出現(xiàn)在中午12：00左右,HN水平最高值出現(xiàn)在中午12：00,且全天變化區(qū)間并不大；濕地松林樣地4種模擬氮沉降濃度處理方式土壤呼吸值日變化不明顯,最高值均出現(xiàn)上午9：00左右；樟樹(shù)林、濕地松林在4種不同模擬氮沉降濃度處理下土壤呼吸速率均有相似的季節(jié)動(dòng)態(tài)變化,與溫度變化走勢(shì)相近,峰值均出現(xiàn)在試驗(yàn)地溫度最高的夏季(6-8月份),最低值均出現(xiàn)在試驗(yàn)地氣溫度最低的冬季(1-2月份)。(2)模擬氮沉降顯著抑制樟樹(shù)林、濕地松林土壤呼吸速率和年累積量,對(duì)照樣地CK與LN.MN.HN樣地的差異性顯著(p0.05,n=9),3種模擬氮沉降處理均降低年累積量,但隨時(shí)間的推移,模擬氮沉降對(duì)土壤呼吸的抑制效果隨之減弱。2種林分之間年均土壤呼吸速率和土壤呼吸年累積量在3種模擬氮沉降濃度處理下差異性顯著(p0.01),均表現(xiàn)為：樟樹(shù)林濕地松林。(3)模擬氮沉降處理對(duì)2種森林類型的土壤呼吸速率的敏感系數(shù)Qlo的影響并不明顯(p0.05)。樟樹(shù)林在4種模擬氮沉降濃度處理下土壤呼吸的溫度敏感系W10值表現(xiàn)出：LNCK)HN)MN;濕地松林土壤呼吸的溫度敏感系數(shù)Q10表現(xiàn)出：CK)MNHN)LN;樟樹(shù)林中的Q10值總體高于濕地松林。(4)土壤溫度是影響土壤呼吸的主要因子之一,土壤溫度控制土壤呼吸速率變異表現(xiàn)為：濕地松林樟樹(shù)林。土壤濕度與土壤呼吸的關(guān)系不明顯,土壤濕度對(duì)土壤呼吸影響表現(xiàn)為：樟樹(shù)林濕地松林。(5)模擬氮沉降明顯減少樟樹(shù)林、濕地松林的有效氮,表現(xiàn)為：濕地松林樟樹(shù)林,模擬氮沉降處理間無(wú)顯著差異。模擬氮沉降增加了土壤中硝態(tài)氮的含量,且土壤硝態(tài)氮含量隨模擬氮沉降水平升高而增大。在樟樹(shù)林和濕地松林中,通過(guò)對(duì)土壤呼吸速率的日動(dòng)態(tài)、季節(jié)動(dòng)態(tài)、年均呼吸速率及年呼吸累積量的對(duì)比,不同模擬氮沉降濃度處理間均表現(xiàn)為：樟樹(shù)林濕地松林。
[Abstract]:Since the last century, nitrogen input from terrestrial ecosystems caused by human activities worldwide has increased 3-5 times, a trend that continues. China's subtropical region has become one of the high nitrogen deposition areas in the world. High nitrogen input has a great influence on soil respiration and the mechanism of biological productivity change in forest ecosystem. This study took camphor forest and Pinus elliottii forest in Hunan Botanical Garden as the research object and simulated nitrogen deposition experiment. Four simulated nitrogen deposition levels, including CK 0 kgN hm-1 a-1, low N LNN 50 kgN hm-2 a-1, medium N MNN 150 kg N hn-1 a-1 and high N HN 300 kg N hm-1 a-1C, were set up, and the camphor forest was analyzed. Responses of soil respiration and its controlling factors to simulated nitrogen deposition in Pinus elliottii forest. The diurnal variation of soil respiration in Pinus elliottii forest was affected. The highest value of soil respiration at CK.LN.MN level appeared at 22: 00-4: 00 in the evening, and the lowest value appeared at around 12:00 at 12: 00 noon, and the whole day variation range was not large. The diurnal variation of soil respiration was not obvious in four simulated nitrogen concentration treatments of Pinus elliottii forest, and the highest value was about 9:00 in the morning. The soil respiration rate of Pinus elliottii forest was similar to that of temperature under four simulated nitrogen concentration treatments. The peak value appeared in June to August in summer when the temperature was the highest, and the lowest value was in the winter with the lowest air temperature. The simulated nitrogen deposition significantly inhibited the soil respiration rate and annual accumulated amount of camphor trees, Pinus elliottii forest, and Pinus elliottii forest. The difference between CK and LN.MN.HN plots was significant (p 0.05). All three simulated nitrogen deposition treatments decreased the annual accumulation, but with the time passing, the three simulated nitrogen deposition treatments decreased the annual accumulative capacity of CK and LN.MN.HN plots, but with the passage of time, there were significant differences between CK and LN.MN.HN plots. The inhibitory effect of simulated nitrogen deposition on soil respiration was decreased. 2. The average annual soil respiration rate and the annual accumulation of soil respiration were significantly different under the three simulated nitrogen deposition concentrations, all of which were: camphor forest wet. The effect of simulated nitrogen deposition on the sensitivity coefficient of soil respiration rate (Qlo) of two forest types was not obvious. The temperature sensitive line W10 of camphor forest under four simulated nitrogen deposition concentrations showed. The temperature sensitive coefficient Q10 of soil respiration in Pinus elliottii forest showed that the soil temperature was higher than that in Pinus elliottii forest, and the soil temperature was one of the main factors affecting soil respiration, and the Q10 value of camphor forest was higher than that of Pinus elliottii forest. The variation of soil respiration rate controlled by soil temperature was shown as follows: Pinus elliottii forest camphor forest, and the relationship between soil moisture and soil respiration was not obvious. The effect of soil moisture on soil respiration was as follows: Pinus elliottii forest. 5) simulated nitrogen deposition significantly reduced the available nitrogen of Pinus sylvestris forest, and the available nitrogen of Pinus elliottii forest was shown as follows: Pinus elliottii forest camphor forest. There was no significant difference between simulated nitrogen deposition treatments. Simulated nitrogen deposition increased the nitrate content in soil, and the nitrate nitrogen content in soil increased with the increase of simulated nitrogen deposition level. Through the comparison of daily, seasonal, annual and annual respiration rate and annual respiration accumulation of soil respiration rate, the different simulated nitrogen deposition concentration treatments were as follows: Pinus elliottii Pinus elliottii forest in camphor tree forest.
【學(xué)位授予單位】：中南林業(yè)科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：S714

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