中国亚热带四种森林类型凋落叶分解过程中不同形态碳和植硅体碳演变规律研究

发布时间：2018-06-16 12:34

本文选题：凋落叶 + 分解速率　；参考：《浙江农林大学》2016年硕士论文

【摘要】：凋落叶作为森林生态系统中凋落物的主要成分,是土壤有机质的主要来源,在土壤质量维持和全球气候变化方面发挥着重要作用。植硅体碳作为一种稳定性碳的形态,随植物的死亡或凋谢后进入土壤,进而影响土壤稳定性碳库的储量。本研究利用~(13)C-NMR技术,分析了中国亚热带4种典型森林类型(毛竹林、马尾松林、杉木林、常绿阔叶林)凋落叶分解过程中不同形态碳化合物信号强度的变化规律;采用碱溶分光光度法,分析了凋落叶分解过程中植硅体碳含量的变化特征。主要结果如下:(1)分析了4种森林类型凋落叶分解过程,结果表明:4种森林凋落叶经过12个月的分解后,质量损失率分别为:常绿阔叶林(53.80%)马尾松林(52.69%)杉木林(48.31%)毛竹林(41.17%),表明毛竹林和杉木林凋落叶比马尾松林和常绿阔叶林凋落叶更难降解。4种森林凋落叶半分解时间表现为10.5~14.5月,95%分解时间表现为3.91~5.27年。随着凋落叶分解时间的推移,4种森林凋落叶中的N含量逐渐提高,C含量和C/N逐渐降低。凋落叶的C含量、C/N与凋落叶质量残存率之间呈极显著正相关(r=0.9010~0.9840,p0.01,n=12),而N含量与凋落叶质量残存率之间呈极显著负相关(r=-0.9211~-0.9831,p0.01,n=12)。(2)研究了4种森林类型凋落叶分解过程中不同形态碳组分~(13)C-NMR波谱特征,结果表明:随分解时间的增加,4种森林凋落叶羰基碳的信号强度显著增加(0.75~2.08倍),芳香碳则小幅增加(25.14~37.37%),而烷氧碳和烷基碳有增有减。4种森林凋落叶的烷氧碳、芳香碳和羰基碳信号强度与凋落叶质量残存率之间均呈现极显著相关性(r=0.8800~0.9301,p0.01,n=12)。除马尾松之外,其余森林凋落叶的烷基碳信号强度与凋落叶质量残存率之间均无显著相关性。相比而言,采用~(13)C-NMR波谱技术比常规指标更能准确预测凋落物的衰减,因而更有利于深入认识凋落叶分解机制。(3)探讨了4种森林类型凋落叶分解过程中植硅体碳的变化规律,结果表明:各种森林凋落叶分解是硅含量、植硅体含量相对积累的过程,不同森林凋落叶植硅体含量在分解过程中的变幅为:毛竹(139.61~169.69 g·kg-1)、马尾松(7.43~10.98 g·kg-1)、杉木(7.12~11.04 g·kg-1)、常绿阔叶林(7.55~10.54 g·kg-1),而植硅体碳含量变幅为:毛竹(24.52~29.29 g·kg-1)、马尾松(81.55~94.23 g·kg-1)、杉木(109.81~123.71 g·kg-1)、常绿阔叶林(80.94~91.59 g·kg-1)。动态分解过程中,毛竹林凋落叶植硅体与植硅体碳含量与其余3种林分之间有显著性差异(p0.05)。毛竹林凋落叶植硅体和植硅体碳释放速率与其余3种森林之间差异也达到显著水平(p0.05)。总之,4种森林类型凋落叶中,马尾松林和常绿阔叶林凋落叶比毛竹林和杉木林凋落叶更易降解。在分解过程中,4种凋落叶中烷氧碳含量随分解时间的进行不断降低,且占比均高于其余碳组分,对凋落叶的分解起决定作用。采用~(13)C-NMR波谱技术更有利于深入认识凋落叶分解机制。毛竹林凋落叶植硅体含量最高,植硅体碳含量最低。4种凋落叶均具有一定的植硅体碳汇潜力,毛竹最大。凋落物分解速率、植硅体产量、植硅体固碳能力等,是引起森林土壤植硅体碳含量差异的重要因素。
[Abstract]:As the main component of litter in the forest ecosystem, the litter is the main source of soil organic matter. It plays an important role in soil quality maintenance and global climate change. As a stable carbon form, plant silicon carbon will enter the soil with the death or withering of plants, and then affect the reserves of soil stable carbon pool. This study used ~ (13) C-NMR technology to analyze the variation of the signal intensity of different forms of carbon compounds in the litter decomposition process of 4 typical Chinese subtropical forest types (bamboos, Pinus massoniana forest, Chinese fir forest and evergreen broad-leaved forest). The change characteristics of the carbon content in the litter decomposition process were analyzed by alkaline solution spectrophotometry. The main results are as follows: (1) the decomposition process of 4 species of forest leaves was analyzed. The results showed that after 12 months of decomposition, the mass loss rates of 4 forest litter were: evergreen broad-leaved forest (53.80%) Pinus massoniana (52.69%) Cunninghamia lanceolata (48.31%) Mao Zhulin (41.17%), indicating that the leaves of Mao Zhulin and Cunninghamia lanceolata were compared to the Masson pine forest and evergreen broad-leaved forest. The deciduous leaves of the forest litter are more difficult to degrade the semi decomposition time of the.4 forest litter, and the time of decomposition is 10.5~14.5 months, and the 95% decomposition time is 3.91~5.27 years. As the litter decomposition time goes on, the content of N in the leaves of 4 species of forest gradually increases, and the content of C and C/N gradually decrease. The C content of litter leaves, C /N and the residual leaf mass residual rate are very significant positive. Correlation (r=0.9010~0.9840, P0.01, n=12), while N content was significantly negatively correlated with the residual leaf mass residual rate (r=-0.9211~-0.9831, P0.01, n=12). (2) the characteristics of ~ (13) C-NMR wave spectra of different forms of carbon fractions in the litter decomposition of 4 forest types were studied. The results showed that the carbonyl carbon letter of 4 forest litters with the increase of decomposition time The intensity of the number increased significantly (0.75~2.08 times) and the aromatic carbon was slightly increased (25.14~37.37%), while alkoxy carbon and alkyl carbon increased the alkoxy carbon, and the signal intensity of aromatic carbon and carbonyl carbon showed significant correlation with the residual leaf mass residual rate (R =0.8800~0.9301, P0.01, n=12). Except for masson pine, the rest forests were in addition to masson pine. There is no significant correlation between the intensity of the deciduous alkyl carbon signal and the residual leaf mass residual rate. Compared with the conventional index, the decay of litter can be predicted more accurately by using ~ (13) C-NMR spectroscopy than the conventional ones. (3) the plant carbon carbon in the litter decomposition process of 4 forest types is discussed. The results show that the decomposition of various forest litter is the content of silicon and the accumulation of the content of the plant silicon, and the variation of the content of the plant silicon in different forest litter is: Bamboo (139.61~169.69 G. Kg-1), masson pine (7.43~10.98 G. Kg-1), Chinese fir (7.12~11.04 G. Kg-1), evergreen broad-leaved forest (7.55~10.54 g kg-1), The carbon content of Phyllostachys is: Bamboo (24.52~29.29 G. Kg-1), Pinus massoniana (81.55~94.23 G. Kg-1), Chinese fir (109.81~123.71 g kg-1), evergreen broad-leaved forest (80.94~91.59 g kg-1). In the dynamic decomposition process, there is a significant difference between the carbon content of the litter and the carbon content of the Phyllostachys pubescens and the other 3 kinds of forests. The difference between the carbon release rate of the body and the phytate and the other 3 forests also reached a significant level (P0.05). In a word, the litter of Masson Pine and evergreen broad-leaved forest was more easily degraded than that of Mao Zhulin and Chinese fir forest in the 4 forest types. In the decomposition process, the content of alkoxy carbon in the 4 species of litter decreased with the decomposition time. And the proportion of the percentage is higher than the other carbon components, which plays a decisive role in the decomposition of litter. The ~ (13) C-NMR spectroscopy is more conducive to the understanding of the decomposition mechanism of the litter. The content of the plant silicon in the litterfall leaves of the bamboo forest is the highest, the lowest.4 species of the Phyllostachys litter has a certain carbon sink potential of the phyllostacht, the largest of the litter is the litter decomposition rate. The yield of silicon carbide and the carbon sequestration capacity of plant silicon are important factors that cause the difference of carbon content in silico soil of forest soil.
【学位授予单位】：浙江农林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S714

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