本文關(guān)鍵詞： 強(qiáng)堿土 土壤呼吸 變化特征 影響因子 降水　出處：《新疆大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：干旱半干旱地區(qū)的土壤無機(jī)碳的儲量巨大,它對于整個區(qū)域乃至全球碳循環(huán)的作用不可忽視。本研究采用LI-8100開路式土壤碳通量測量儀測定了無植被生長、有機(jī)質(zhì)含量極少的強(qiáng)堿土土壤呼吸。野外采取土柱并滅菌處理,通過比較其無機(jī)與有機(jī)土壤呼吸所占比例,確定強(qiáng)堿土土壤呼吸的主導(dǎo)方式。同時在野外觀測了其春、夏、秋季的土壤呼吸速率、溫度(氣溫和地溫)、濕度(空氣相對濕度和土壤濕度)數(shù)據(jù),分析它們之間的相關(guān)關(guān)系,并通過通徑分析,獲得不同季節(jié)對土壤呼吸影響最大的直接影響因子及間接因子,依此建立不同類別的多種回歸模型,在精度檢驗及簡單易行的原則上,得到各季節(jié)土壤呼吸預(yù)測的最優(yōu)模型,且以這些模型的建模因子討論強(qiáng)堿土土壤呼吸日和季節(jié)變化的機(jī)理。此外,在室內(nèi)模擬了冬季低溫環(huán)境下的土壤呼吸特征,以及在野外模擬不同降水強(qiáng)度下的土壤呼吸變化。最終以說明強(qiáng)堿土在不同環(huán)境下的土壤呼吸特征。主要研究結(jié)果如下:(1)強(qiáng)堿土土壤呼吸中,無機(jī)呼吸部分占到總的呼吸的99.37%。其主導(dǎo)了日變化和季節(jié)變化,有機(jī)呼吸部分的影響可忽略。(2)春、秋季土壤呼吸與氣溫、空氣相對濕度和土壤濕度均達(dá)到了極顯著相關(guān),且與氣溫的相關(guān)性最強(qiáng)。夏季土壤呼吸與溫、濕度四因子均存在極顯著的相關(guān)關(guān)系,與地溫的相關(guān)性最高。通徑分析表明,氣溫是春、秋季土壤呼吸的最大直接影響因子,夏季則為地溫因子,且三季節(jié)均以土壤濕度的間接作用最大。此外,溫、濕度的耦合控制了土壤呼吸的變化,10cm處氣溫和土壤濕度所建的方程是春、秋季土壤呼吸的最佳預(yù)測模型,精度分別為92.67%和77.23%。而夏季土壤呼吸的最佳預(yù)測模型則為與10cm處氣溫、地溫、空氣相對濕度和土壤濕度所建的4因子方程,其估測精度為84.99%。(3)春、秋季的土壤呼吸日變化為單峰型,其峰值出現(xiàn)時間分別為14:00和10:00,日間段以釋放CO2為主,夜間段則在大量的吸收CO2,但整體上春季以釋放CO2為主(釋放量為0.07μmol·m-2·s-1),而秋季則以吸收CO2為主(吸收量為0.05μmol·m-2·s-1)。夏季土壤呼吸日變化呈雙峰型,第一峰值出現(xiàn)在9:00~10:00,第二峰值則出現(xiàn)在21:00左右,且其土壤呼吸速率僅在5:00~11:00期間以及21:00左右為正值,其余時段則為負(fù)值,其整體上吸收CO2,吸收量達(dá)到0.14μmol·m-2·s-1。模擬冬季土壤呼吸發(fā)現(xiàn),低溫下,強(qiáng)堿土能吸收大量的CO2,且溫度越低,吸收的量越多。(4)強(qiáng)堿土土壤呼吸的變化機(jī)理,主要是土壤中的碳酸鹽(Ca CO3等)與H2O和CO2的化學(xué)反應(yīng)生成重碳酸鹽而吸收CO2,使得夜間和日間的低溫時段土壤呼吸速率值為負(fù)。而溫度高的日間段,重碳酸鹽遇熱分解釋放出CO2,但當(dāng)溫度達(dá)到一定的界限后(10cm處氣溫和地溫分別超過30℃、26℃),高溫反而激發(fā)了碳酸鹽與H2O-CO2的反應(yīng)速率而吸收大量的CO2,但前提是土壤濕度應(yīng)保持在一個較高的水平。(5)小雨處理激發(fā)了土壤呼吸,在降水過程中,其比對照增加了320.69%,降水后的增長為58.82%,在降水后22h,土壤呼吸速率恢復(fù)到對照水平。中雨處理在降水過程中,其比對照減少了48.27%,但在降水后則整體增加了29.41%,降水后37h,土壤呼吸速率大致恢復(fù)到與對照相近水平。大雨處理使得強(qiáng)堿土能吸收更多的CO2,降水過程中和降水后的土壤呼吸速率,相較對照分別減少306.89%和188.24%。
[Abstract]:The soil inorganic carbon in arid and semi arid regions of the huge reserves, it is for the whole region and the global carbon cycle can not be ignored. This study determined by LI-8100 without vegetation growth in open soil carbon flux meter, alkali soil organic matter content of soil respiration. Rarely take soil column and field sterilization proportion through the comparison of the inorganic and organic soil respiration, soil respiration to determine the dominant mode of alkaline earth strong. At the same time in the field observation of the spring, summer and autumn, the soil respiration rate, temperature (temperature) and humidity (relative humidity and soil moisture) data, analysis of the relationship between them, and through path analysis through the different season the most direct impact factors and indirect factors on soil respiration, establish various different categories in the regression model, accuracy test and simple in principle, the The optimal model of soil respiration seasonal prediction, and the modeling of these models to discuss the mechanism of the change of factors of soil alkali soil respiration and the seasons. In addition, characteristics of soil respiration in winter with low temperature environment is simulated in laboratory, and in the field simulated rainfall intensity of soil respiration. Finally in order to illustrate the characteristics of soil respiration in alkali soil under different environmental conditions. The main results are as follows: (1) soil respiration in alkali, inorganic respiration accounted for the total respiration 99.37%. dominated the diurnal and seasonal changes, the effect of organic respiration part can be ignored. (2) the spring and autumn soil respiration and temperature, air relative humidity and soil humidity reached a significant correlation with temperature, and the correlation between soil respiration and temperature. The strongest in summer, there was a significant correlation between the four highest temperature and humidity factor correlation. Path analysis showed that the gas The temperature of soil respiration in autumn Shichun, the largest direct impact factor, summer is the temperature factor, and the three season are the indirect effects of soil moisture. Moreover, temperature change, humidity coupling control of soil respiration, the 10cm temperature and soil humidity equation is the best model of spring, autumn soil respiration, the accuracy is 92.67% and 77.23%. respectively and the optimal prediction model of soil respiration in summer is temperature, and soil temperature at 4 10cm, the equation of air relative humidity and soil moisture, the estimation accuracy of 84.99%. (3) spring, the diurnal change of soil respiration in autumn was single peak type, the peak time was at 14:00 and at 10:00 the day to release the CO2, at night in a large number of absorption of CO2, but the whole spring to release CO2 (release 0.07 mol - m-2 - s-1), and CO2 (mainly in autumn absorption absorption was 0.05 mol m-2. S-1). In summer, the diurnal change of soil respiration in Shuangfeng, the first peak in the 9:00~10:00, the second peak appeared at about 21:00, and the soil respiration rate only during 5:00~11:00 and around 21:00 in the rest time is negative, the absorption of CO2, reached 0.14 mol - m-2 - s-1. simulation of soil in winter breathing found absorption under low temperature, alkali soil can absorb a large amount of CO2, and the lower the temperature, the more the amount of absorption. (4) the change mechanism of alkali soil respiration, soil is mainly carbonate (Ca CO3) and H2O and CO2 chemical reaction of bicarbonate and absorption of CO2, the at the low temperature of soil respiration at night and daytime value is negative. While the daytime temperature is high, bicarbonate in thermal decomposition of the release of CO2, but when the temperature reaches a certain threshold (air temperature and soil temperature at 10cm were more than 30 DEG, 26 DEG C), but to stimulate carbon at high temperature The reaction rate of acid salt and H2O-CO2 and absorb a large amount of CO2, but the premise is the soil humidity should be maintained at a relatively high level. (5) the rain treatment stimulated soil respiration in the precipitation process, an increase of 320.69% compared with the control, after the rainfall of 58.82% growth in the precipitation of 22h after recovery of soil respiration the rate to the level of control. Moderate treatment in the precipitation process, the reduction of 48.27% compared with the control, but after rainfall in the overall increase of 29.41%, after precipitation 37h, soil respiration rate is restored to the control level. The heavy rain makes similar alkali soil can absorb more CO2, the precipitation process of soil respiration after neutralization precipitation compared with the control, respectively by 306.89% and 188.24%.

【學(xué)位授予單位】：新疆大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S154

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