【作者】 郭红艳；

【导师】 卢琦；

【作者基本信息】 中国林业科学研究院 ， 水土保持与荒漠化防治， 2013， 博士

【摘要】 土壤在全球碳平衡中具有举足轻重的作用，而土地利用变化对土壤碳的影响也是极其敏感的。本论文针对我国西南岩溶地区土地石漠化严重导致的土地退化、土壤质量下降如何影响土壤的碳库和碳排放的科学问题，在石漠化治理典型地区——贵州省关岭自治县花江峡谷区，通过选取未石漠化土地（非石漠化土地和潜在石漠化土地）和石漠化土地（轻度、中度、重度、极重度）监测样地，测定了土壤中的有机碳和无机碳含量，采用动态气室法（Li-8100,USA）于2012年-2013年测定了不同季节的土壤呼吸速率，采用标准溶蚀试片法进行了岩溶作用对土壤碳库和碳排放影响的野外监测试验；通过关岭县治理前后石漠化程度监测数据分析，定量评价了石漠化治理工程对区域土壤碳库和土壤碳排放量的影响。本论文的主要结论如下:（1）土壤的有机碳含量：未石漠化土地中非石漠化土地的土壤有机碳含量大于潜在石漠化土地的；石漠化土地中，重度和极重度石漠化土地的土壤有机碳含量高于中度石漠化土地的；未石漠化土地的土壤有机碳含量大于石漠化土地的。土壤的无机碳含量：未石漠化土地中，非石漠化土地样地草地的无机碳密度最大，约为灌木地的2倍，裸地的5倍，这说明土壤无机碳密度与地表植被类型有关，潜在石漠化土地中，各种地表植被类型的无机碳密度值均明显低于非石漠化土地的；不同等级石漠化土地的土壤无机碳密度小于未石漠化土地的。未石漠化土地中，非石漠化土地和潜在石漠化土地的土壤平均碳密度分别为14320.15t/km~2和6331.16t/km~2；石漠化土地中轻度、中度、重度和极重度石漠化土地的土壤的平均碳密度分别为2251.25t/km~2，1012.14t/km~2，333.67t/km~2和278.47t/km~2；岩溶区土地的碳密度遵循非石漠化土地＞潜在＞轻度＞中度＞重度＞极重度石漠化土地的变化规律，这主要与土壤总量有关。（2）未石漠化土地土壤呼吸速率（碳排放速率）具有明显的季节变化特征，其中非石漠化土地的土壤呼吸速率遵循植物生长的季节发生大小变化，夏季的最高，其次是秋季，春季的略高于冬季，基本持平，潜在石漠化土地中春季最大、秋季高于夏季、冬季最小，其4季的平均土壤呼吸速率明显低于非石漠化土地的，潜在石漠化土地的土壤呼吸速率变化规律具有不确定性，有待进一步获取数据进行验证；不同程度的石漠化土地的土壤呼吸速率均表现为秋季＞夏季。当未石漠化土地退化为石漠化土地后，土壤呼吸则不再遵循植物生长的季节顺序发生大小变化，土壤呼吸随季节的这种变化规律被打破。未石漠化土地中，非石漠化土地和潜在石漠化土地的土壤平均年碳排放量分别为850.21t/km~2和445.88t/km~2；石漠化土地中轻度、中度、重度和极重度石漠化土地土壤的平均年碳排放量分别为515.83t/km~2，287.38t/km~2，72.59t/km~2和44.39t/km~2。土地的平均碳排放量与土壤的碳排放速率和土壤覆盖度有关。（3）岩溶作用增加了土壤的碳汇能力，在未石漠化土地中非石漠化土地和潜在石漠化土地的年岩溶碳汇量分别为0.35t/km~2和0.50t/km~2；不同程度石漠化土地的年碳汇量分别为0.89t/km~2、1.28t/km~2、1.31t/km~2、和1.45t/km~2，岩溶作用碳汇效果取决于土地的石漠化程度，其对未石漠化土地的影响甚微，而随着土地石漠化程度的加剧，影响加大；这与在其他岩溶地区的研究结果不同，原因是该地区环境条件复杂，干旱少雨可能是主要的原因。（4）关岭县实施的石漠化综合治理工程改善了当地的生态环境，表现在土地格局的变化。其中：非石漠化土地面积增加69.06km~2、潜在石漠化土地面积增加2.07km~2，轻度石漠化土地面积增加了12.21km~2、中度石漠化土地面积减少78.14km~2、重度石漠化土地面积减少55.72km~2、极重度石漠化土地面积增加52.21km~2。通过治理，2005年到2010年全县土壤碳排放量增加了4.77万t，土壤碳库增加了88.18万t；碳储存量共增加了83.41万t，相当于关岭县岩溶区每平方公里增加了637.67t C。研究结果为定量评价岩溶石漠化治理对土壤碳汇功能的影响提了供科学依据。更多还原

【Abstract】 The soil play a key role in the global carbon balance, while the soil carbon is sensitive tothe land use change. The paper addresses the scientific question that how the land degradationand the decreasing of the quality of soil will influence the soil carbon emissions, which wascaused by the rocky desertification in the Karst region of southwest China. We selectedmonitoring plots include Not rocky desertification land(Non-rocky desertification land andpotential rocky desertification land) and desertification land(slight, middle,serious,significantslight) in the typical rocky desertification management area Huajiang karst gorge in Guanlingcounty of Guizhou province. We measured the soil organic carbon and soil inorganic carbon inthe not rocky desertification land and rocky desertification land and used the Li-8100automated soil CO2flux system to monitor the seasonal variations of soil respiration from2012-2013in the fields, We used test specimens made from lithology rocky to monitor thecorrosive rate,to study the influence of Karst process on the soil carbon pool and soil carbonemissions. Through the monitor data analysis of the area and degrees of rocky desertificationland of Guanling County before and after the rocky desertification management. The influenceon the soil carbon pool and soil carbon emissions by rocky desertification management wasevaluated quantitatively. The main results are as follows:(1)Soil organic carbon content: the soil organic carbon content of Non-rockydesertification land is higher than that of potential rocky desertification land, among rockydesertification land, the soil organic carbon content of serious and significant serious rockydesertification land are higher than that of the slight rocky desertification land; the soil organiccarbon content of Not rocky desertification land is higher than that of rocky desertificationland.In non-Rocky desertification land, the soil inorganic carbon density of grass land was thelargest, which was two times of shrub land and five times of bare land. It indicate that the soilinorganic carbon density had a great relevance with the surface vegetation types. In the potential-Rocky desertification land, the soil inorganic carbon density was lower than that ofnon-Rocky desertification land. In the Rocky-desertification land, the soil inorganic carbondensity was the lowest.The average soil carbon density of Non-rocky desertification land and potential rockydesertification land are respectively14320.15t/km~2and6331.16t/km~2, and in rockydesertification land the average soil carbon density of different degree land arerespectively2251.25t/km~2,1012.14t/km~2,333.67t/km~2,278.47t/km~2; the carbon density ofdifferent lands follow the changing rule that non-rocky desertification land＞potential＞slight＞middle＞serious＞significant serious rocky desertification land, which is mainly determinedby the soil coverage and soil depth.(2) The soil respiration rate in Rocky region had a very high concordance with thedegree of Rocky desertification, and also had obvious seasonal variation. The soil respirationrate of non-rocky desertification land had obvious seasonal variation, the change rule wasbroken while the land become Rocky desertification land as the rule of soil respiration rate nolonger follow the plant growth season order to change, the soil respiration rate in summerseason is the highest,the second is autumn season, and that in spring is a little higher than thatin winter,which are basically flat, the average soil respiration rate of the four seasons is lowerthan that in Non rocky desertification land obviously, the rule of non-Rocky desertification ofsoil respiration is follow the four seasons, and this abnormal change law is uncertain, further toget data for validation is needed; However, the change rule was broken while the not rockydesertification land degrade into rocky desertification land, the soil respiration rate in autumn isthe highest, and followed by summer, spring, winter of different rocky desertification lands.The annual average soil respiration rate of Non-rocky desertification land and potentialrocky desertification land are respectively850.21t/km~2and445.88t/km~2, and in rockydesertification land the annual average soil carbon density of different degree land arerespectively515.83t/km~2，287.38t/km~2，72.59t/km~2and44.39t/km~2; The annual soilcarbon emissions has correlation with the soil respiration rate and the soil coverage. (3)The Karst process increase the capacity of soil carbon sinks, the annual carbon sinks ofNon-rocky desertification land and potential rocky desertification land in Not-rockydesertification land type are respectively0.35t/km~2and0.50t/km~2；the annual carbon sinks ofdifferent degree rocky desertification land type are respectively0.89t/km~2,1.28t/km~2,1.31t/km~2, and1.45t/km~2；the influence of Karst process on soil carbon pool and soil carbonemissions depend on the degree of rocky desertification land, which has little influence on Notrocky desertification land, but as the degree increased,the influence also increased; the result isdifferent from other research in Karst region, the reason is that this area is dry and less ofrainfall, the lower soil water depressed the Karst process.(4)The rocky desertification comprehensive management impeneted in Guanling Countyimproved the eco-environment, which reflected in the change of degree and area of the land.Among them, the area of non-rocky desertification land increased69.06km~2and potentialrocky desertification land increased2.07km~2, slight rocky desertification land increased12.21km~2, middle rocky desertification land decreased78.14km~2, serious rocky desertificationland decreased55.72km~2,significant serious rocky desertification land increased55.72km~2.Through rocky desertification contral managment from2005to2010, the total soil carbonemissions increased47.7thousand t, the soil carbon pool increased881.8thousand t, thecarbon storage increased834.1thousand t, which was equal to637.67t C every squarekilometers in the Karst region of this County. The research has provided quantitative evaluationof the influence of the rocky desertification management on soil carbon storage function.更多还原