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模拟增温对峨眉冷杉林凋落物分解的影响
Alternative TitleThe Effects of Simulated Warming on Abies fabri Forest Litter Decomposition
Language中文
陈晓丽
Thesis Advisor王根绪 ; 杨燕
2014
Degree Grantor中国科学院研究生院
Place of Conferral北京
Degree Name硕士
Degree Discipline自然地理学
Keyword山地森林 凋落物分解 气候变暖 凋落物厚度 土壤生化性质
Abstract峨眉冷杉(Abies fabri (Mast.) Craib)是贡嘎山亚高山暗针叶林的优势树种和建群种。本文采用开顶式生长箱和加热电缆联合增温方式(OTC-cable)模拟增温,研究增温和凋落物厚度对峨眉冷杉林凋落物分解的影响;同时,在实验样方内人工添加同等厚度的新鲜凋落物,以观察凋落物分解对土壤生化性质的影响。研究结果表明: 1. 增温和凋落物厚度对失重率的影响:随凋落物厚度增加,失重率变大,且差异显著;增温使得不同厚度凋落物失重率均增大,增幅均在6%左右。凋落物失重率随凋落物厚度增加而增大,随温度增加而增大。 2. 峨眉冷杉林混合凋落物在分解4年后,各营养元素和灰分、木质素的含量如下:碳(C):30-40%,氮(N):1.1-1.6%,磷(P):0.5-1.7 g?Kg-1,钾(K):2.1-3.3 g?Kg-1,镁(Mg):2.6-6.6 g?Kg-1,钙(Ca):57-252 g?Kg-1,锰(Mn):326-587 mg?Kg-1,铜(Cu):42-95mg?Kg-1;灰分:24-40%,木质素:20-40%。 随着凋落物厚度的增加,凋落物C、N、K的分解加强,P、Ca的分解减弱,C:N也增大;厚度对凋落物Mg、Mn、Cu及灰分和木质素分解无显著影响。增温抑制薄凋落物C、P分解及厚凋落物C、K分解,促进厚凋落物P、Ca、Mg、Mn、Cu分解;对三个厚度凋落物N分解及中等厚度C和P影响不明显,凋落物C:N大致呈增大趋势。增温抑制中等厚度凋落物Mg、Mn、Cu的分解。温度上升抑制灰分物质分解,促进木质素分解。增温与凋落物厚度间交互作用显著。 3. 表层土壤化学性质如下:呈弱酸性(pH值4.1-5.5),碳(C):2-38%,氮(N):0.1-1.6%,磷(P):0.5-1.3%。表层土壤酸碱性受不同厚度的凋落物分解及增温的影响不大,且并不随土壤深度而表现出明显差异。表层土壤全磷含量受不同厚度凋落物分解和增温处理的影响较小且不随土壤深度而表现出差异。增温使得土壤全碳和全氮含量降低,程度因凋落物厚度和土壤深度而所有差异。随着土壤深度的增加,土壤全氮含量降低。 表层土壤酶活性:过氧化氢酶(catalase):1-6 EU,多酚氧化酶(polyphenol oxidase):0.3-3.1 EU,脲酶(urease):8-30 EU。随着土壤深度的增加,表层土壤过氧化氢酶、多酚氧化酶活性增大,脲酶活性降低,具统计学显著性。随凋落物厚度的增加,表层多酚氧化酶活性降低,而脲酶活性增加。增温抑制表层土壤多酚氧化酶活性却增大脲酶活性,不受凋落物厚度和土壤深度的影响;对土壤过氧化氢酶活性的影响则较为复杂。土壤深度与凋落物厚度和增温的交互作用显著。 4. 不同厚度凋落物分解进行中长期(4年)增温处理研究发现:增温能加速凋落物分解,却减缓含碳物质和灰分物质的分解;凋落物厚度增加抑制灰分物质分解,却促进凋落物分解。增温和凋落物分解对表层土壤酸碱性和全磷含量无明显影响;增温会加速表层土壤碳、氮循环,凋落物分解也加速土壤碳、氮循环;增温和凋落物分解会减少表层土壤碳库的碳储量。增温抑制表层土壤多酚氧化酶活性却增大脲酶活性,对过氧化氢酶活性的影响较复杂,随凋落物厚度等因素而不同;凋落物分解对过氧化氢酶活性作用不明显,而随凋落物厚度的增加,多酚氧化酶活性降低,脲酶活性增加。
Other AbstractAbies fabri (Mast.) Craib is dominant tree species and edificator in dark coniferous forests in Mount Gongga. In this study we used open top chamber plus heating cable combined warming (OTC-cable) to comparatively study the effects of simulated warming and litter thickness on Abies fabri forest litter decomposition. Simultaneously, to reaseach the effect of litter decomposition on soil biochemical properties, artifically added fresh litter with same density and proportion to plots. The results showed: 1. The effects of warming and litter thickness on the mass lose ratio: as the thickness of litter increased, the mass lose ratio of litter heightened, and the difference was significant. Warming made mass lose ratio of litter with various thickness bigger, 6% approximately. We can see that the mass lose ratio of litter increased, as the thickness of litter added and warmed. 2. After 4-years decomposition, the some kinds of nutrient elements content of Abies fabri forest mixed litter as followed: carbon(C): 30-40%, nitrogen(N): 1.1-1.6%, phosphorus(P): 0.5-1.7 g?Kg-1, potassium(K): 2.1-3.3 g?Kg-1, magnesium(Mg): 2.6-6.6 g?Kg-1, calcium(Ca): 57-252 g?Kg-1, 326-587 mg?Kg-1, cuprum(Cu): 42-95 mg?Kg-1, ash: 24-40%, lignin: 20-40%. Because of thicker litter, C, N and K decomposed faster while P and Ca decomposed slower, and bigger C:N, as well, the decomposition of Mg, Mn, ash and lignin didn’t change observably. And temperature rising hindered least-thick litter C and P decomposition, and most-thick litter C and K decomposition, expedited most-thick P, Ca, Mg, Mn and Cu decomposition, nevertheless had no effect on litter N and mid-thick C and P decomposition, litter C:N almost largened. It also inhabited mid-thick litter Mg, Mn and Cu decomposition. Warming hindered ash decomposition, accelerated lignin decomposition. Warming significantly interated with litter thickness. 3. The chemical properties of surface soil as followed: slightly acidic (pH: 4.1-5.5), carbon(C): 2-38%, nitrogen(N): 0.1-1.6%, phosphorus(P): 0.5-1.3%. Surface soil’s acid-base property wasn’t affected by litter with different thicknesses decomposition and warming, otherwise it didn’t change with soil depth, obviously. The variation of soil total phosphorus content was same as soil pH, almost unaffected. Warming also reduced soli TC and TN contents, degree varied with litter thickness and soil depth. When soil deepened, soil TN content lowered. Surface soil enzyme activity: catalase: 1-6EU, polyphenol oxidase: 0.3-3.1EU, urease: 8-30EU. Along with the surface soil depth deepened, soil catalase and polyphenol oxidase activities increased, while urease activity decreased, and the effect was statistically significant. As the bigger thickness of litter, surface soil’s polyphenol oxidase activity reduced while urease activity augemented. Warming inhibited surface soil’s polyphenol oxidase activity, but augemented urease activity, the effect didn’t vary with litter thickness and soil depth. However the influence on soil catalase was much complex, there were evident interactions between soil depth and litter thickness and warming. 4. Study on litter decomposition with various thicknesses for medium and long term warming showed: warming sped up litter decomposition, however slowed down the decomposition of carbonaceous matter and ashy substance. The thicker litter inhabited ashy substance decomposition, while accelerated litter decomposition. Warming and litter decomposition had tiny influence on surface soil acid-base property and total phosphorus content, but warming sped up surface soil carbon and nitrogen cycle, litter decomposition also sped up that. That was `warming and litter decomposition cut down carbon reserve in soil carbon pool. Temperature rising inhabited surface soil polyphenol oxidase activity while increased activity of urease, had complex effect on catalase activity according to litter thickness. And litter decomposition didn’t affected catalase activity
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/7997
Collection山地表生过程与生态调控重点实验室
Recommended Citation
GB/T 7714
陈晓丽. 模拟增温对峨眉冷杉林凋落物分解的影响[D]. 北京. 中国科学院研究生院,2014.
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