新疆天山云杉林土壤有机碳及组分特征研究

发布时间：2018-06-19 19:35

本文选题：天然云杉林 + 土壤有机碳　；参考：《北京林业大学》2015年硕士论文

【摘要】：全球气候变化形势日益严峻,作为陆地生态系统碳库之首的森林土壤碳库,在调节碳源与碳汇间的收支平衡、减缓诸如二氧化碳等大气中的温室气体含量上升等方面扮演着不可替代的角色。而土壤有机碳是土壤碳最重要的部分,其含量及矿化特征已成为碳循环领域中的研究热点。因此本研究选择天山乌鲁木齐水西沟境内的森林生态系统定位研究站作为研究区,并分别选取5个海拔梯度(1800-2000m、2000-2200m、 2200-2400m、2400-2600m、2600-2800m)下的土壤作为研究对象,对土壤有机碳含量、微生物碳含量及其变化特征进行了分析,同时对土壤有机碳矿化过程做了研究,并利用单指数、双指数方程对有机碳矿化过程进行了拟合,最后选出最优拟合模型—双指数方程作为拟合分析手段。进而通过数学模型—双指数方程拟合得出土壤活性有机碳、缓效性有机碳的含量,并算出惰性有机碳的含量,进一步利用单因素分析等方法探讨了有机碳及其组分在空间上的变化特性。研究结果显示：5个海拔梯度的云杉林下土壤有机碳含量皆表现出相同的变化趋势：即随土层的加深其含量逐渐降低,表层富集现象极为明显。土层间有机碳含量的变化幅度要明显高于海拔间的变化幅度,即由土层深度变化引起的土壤有机碳含量变化要高于由海拔梯度变化所产生的含量变化。不同海拔同层土壤有机碳含量与云杉林郁闭度、树高、胸径一样均表现出先减少后增加再减少的变化规律；不同海拔梯度天山云杉林下土壤微生物碳含量变化趋势与土壤有机碳含量变化趋势基本一致,即其含量随土壤深度的增加而呈下降的趋势,0-40cm土层微生物碳含量占整个剖面的比例高达61.34%-79.30%,表层富集现象同样明显。不同海拔40cm以上两个土层同层间微生物碳含量表现出先减少后增加再减少的变化规律,而5个海拔的40cm以下相同土层间微生物碳含量均无显著性差异；云杉林各层土壤有机碳矿化均表现出初期强度较大,但随着反应进行,矿化速率逐渐变缓,反应强度减弱。表层土壤有机碳矿化剧烈程度随海拔梯度的增加呈现出先降低再增加最终降低的变化特性；双指数方程对土壤有机碳的矿化拟合效果要优于单指数方程；云杉林土壤剖面中Co(活性有机碳)、Cs(缓效性有机碳)和Cr(惰性有机碳)三者含量表现出随着土壤深度的加深而逐渐降低的垂直变化特征,云杉林土壤惰性有机碳含量变化特点与相应土壤剖面的有机碳含量、微生物碳含量的变化趋势基本一致；云杉林不同海拔土壤活性有机碳、缓效性有机碳、惰性有机碳所占总有机碳的比例大小关系为：Cr/SOC＞Co/SOC＞Cs/SOC,土壤惰性对有机碳起到主要影响作用,而活性有机碳、缓效性有机碳含量对土壤有机碳含量的影响很小。
[Abstract]:Global climate change is becoming more and more serious. Forest soil carbon pool, which is the first carbon pool in terrestrial ecosystem, regulates the balance of income and expenditure between carbon source and carbon sink. Slowing the rise of greenhouse gases in the atmosphere, such as carbon dioxide, plays an irreplaceable role. Soil organic carbon is the most important part of soil carbon, and its content and mineralization characteristics have become the research focus in the field of carbon cycle. Therefore, this study selected forest ecosystem location research station in Urumqi, Urumqi, Tianshan as the study area, and selected five soils under the gradient of altitude 1800-2000mC2000 ~ 2200m, 2200-2400mA2400-2600mP2600-2800m as the research object, and the soil organic carbon content was studied. The microbial carbon content and its changing characteristics were analyzed, and the mineralization process of soil organic carbon was studied, and the process of organic carbon mineralization was fitted by single index and double index equation. Finally, the optimal fitting model-double exponential equation is selected as the fitting analysis method. Then the content of soil active organic carbon and slow-acting organic carbon was obtained by fitting the mathematical model-double exponential equation, and the content of inert organic carbon was calculated. Furthermore, the spatial variation characteristics of organic carbon and its components were investigated by means of single factor analysis. The results showed that the soil organic carbon content under five elevation gradients showed the same change trend: the soil organic carbon content decreased gradually with the deepening of soil layer, the surface layer enrichment phenomenon was very obvious. The change range of soil organic carbon content is obviously higher than that of altitude, that is, the change of soil organic carbon content caused by the change of soil depth is higher than that caused by the change of elevation gradient. Soil organic carbon content and canopy density, tree height and DBH in the same layer at different elevations all showed the change law of decreasing first and then decreasing; The variation trend of soil microbial carbon content in different elevation gradients was basically the same as that of soil organic carbon content. That is to say, the soil microbial carbon content in 0-40cm soil layer accounts for the proportion of 61.34-79.30 in the whole section with the increase of soil depth, and the enrichment phenomenon in the surface layer is also obvious. The microbial carbon content in the same layer of the two layers above 40cm at different elevations showed the law of decreasing first and then decreasing, but there was no significant difference in microbial carbon content between the same soil layers under 40cm at 5 elevations. Soil organic carbon mineralization in all layers of Picea lanceolata forest showed high initial strength, but with the reaction, the mineralization rate gradually slowed down and the reaction intensity weakened. The mineralization intensity of soil organic carbon in surface soil decreased first and then decreased with the increase of elevation gradient, and the fitting effect of double index equation for soil organic carbon mineralization was better than that of single index equation. In soil profile of Picea lanceolata forest, the contents of CsC (slow active organic carbon) and Cr (inert organic carbon) in soil profile of Picea lanceolata forest showed the vertical variation characteristics of decreasing gradually with the deepening of soil depth. The variation characteristics of soil inert organic carbon content in Picea lanceolata forest are basically consistent with the corresponding soil profile organic carbon content and microbial carbon content, and the soil active organic carbon and slow-acting organic carbon in Picea lanceolata stand at different elevations. The ratio of inert organic carbon to total organic carbon is as follows: Cr-SOC > Co- / SOC > Cs / SOC. soil inert plays a major role in organic carbon, while active organic carbon, slow-acting organic carbon content has little effect on soil organic carbon content.
【学位授予单位】：北京林业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S714.2

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