凋落叶分解论文：中亚热带四种树种凋落叶分解对碳氮磷调控的响应.doc

凋落叶分解论文：中亚热带四种树种凋落叶分解对碳氮磷调控的响应【中文摘要】凋落物作为分解者的物质和能量的来源,在生态系统养分循环的过程中发挥着重要的作用。本文以湿地松(Pinus elliottii)林、马尾松(Pinus massoniana)林、针阔混交林、常绿阔叶林的代表性树种为研究对象,采取尼龙网袋法,开展中亚热带不同树种凋落叶分解对碳氮磷调控响应的原位模拟研究,旨在理解凋落物养分归还的基本规律,及其对N沉降等全球变化的响应机制,从而为森林的经营管理提供科学依据。主要结论如下：(1)氮磷添加对湿地松凋落叶原位分解试验的结果表明：N添加()提高分解过程中凋落叶N浓度,N含量表现为分解前期积累、后期释放；P添加()提高分解过程中凋落叶P浓度,P含量持续积累；N和P同时添加()提高N和P浓度,分解前期N、P含量积累,后期释放；而不同处理的C含量均表现为释放。N、P添加对湿地松针叶分解速率和养分释放过程存在耦合作用。(2)碳氮磷添加对马尾松和苦槠(Castanopsis sclerophylla)凋落叶原位分解试验的结果表明：从整个分解过程来看,C添加()对马尾松凋落叶C浓度影响不显著,但可以提高阔叶林苦槠凋落叶C浓度；可以明显提高马尾松林凋落叶N浓度,但对苦槠凋落叶N浓度表现影响不显著；可明显提高马尾松和阔叶林凋落叶P的浓度,且可相应的提高马尾松凋落叶N的浓度。540 d的分解期间内、及对马尾松和苦槠凋落叶质量分解速率影响不显著。(3)碳氮磷添加对针阔混交林中马尾松和枫香(Liquidambar formosana)(1：1)混合凋落叶分解试验结果表明：和的凋落叶C浓度明显低于其他处理；和的凋落叶N浓度高于其他处理；和的凋落叶P浓度高于其他处理,且影响明显高于单独的、和,不同处理的凋落物分解质量衰减差异显著,整体上表现为快-慢-快的分解模式。(4)碳氮磷添加对凋落叶分解过程的影响还表现在凋落叶下土壤微生物类群多样性和关键酶活性的变化。在凋落叶分解180 d和540 d时的影响为显著提高蔗糖酶的活性,180 d还表现为显著提高酸性磷酸酶的活性；在凋落叶分解180 d表现为显著提高酸性磷酸酶的活性；在凋落叶分解540 d时表现为显著提高酸性磷酸酶的活性。综上所述,树种对碳氮磷添加的响应机制比较复杂,且不同的树种对碳氮磷添加的响应机制也是不同的。碳氮磷添加对中亚热带森林生态系统凋落叶分解养分归还规律的影响还有待深入而全面地剖析。【英文摘要】Leaf Litter, as the source of decomposers matter and energy plays an important role in the process of nutrient cycling in ecosystems. In this paper, the representative tree species in slash pine(Pinus elliottii) forest、pine (Pinus massoniana) forest, mixed forest and evergreen forest were selected to study their foliar litter decomposition. On the purpose of understanding the basic nutrient return regulation and the response to global changes of litter, the method of Nylon mesh bags was used to study the response of litter decomposition to carbon, nitrogen and phosphorus additions in mid-subtropical zone, China. All these are helpful to provide some scientific basics for forest management. Major conclusions as follows:(1) The results of effects of nitrogen and phosphorus additions to the decomposition of slash pine needles showed that:N addition (N) increased the N concentration in the process of litter decomposition, N accumulated in the early time of decomposition time, and released in the late time of decomposition time. P addition (P) increased the P concentration in the process of litter decomposition, P accumulated in the whole time of litter decomposition. N and P addition (N+P) increased the N and P concentration, N and P accumulated in the early time of decomposition, and released in the late period of decomposition. But C at all treatments released during the whole experiment period. N and P additions play a coupling effect for litter decomposition rate and nutrient release.(2) The results of effects of carbon, nitrogen and phosphorus additions to the litter decomposition of Masson pine and Castanopsis sclerophylla showed that:The effect of C addition to litter C concentration of Masson pine is not significant, but litter C concentration increased for Castanopsis sclerophylla. N increased the litter N concentration of Masson pine, but the N concentration of Castanopsis sclerophylla was not significant different between N and without N addition. P increased litter P concentration of both species, and P also increased litter N concentration of Masson pine. The effect of C, N and P to mass loss rate of both species were not significant.(3) The results of effects of carbon, nitrogen and phosphorus additions to mixed litter Masson pine and Liquidambar formosana (1:1) showed that:The litter C concentrations for C and C+N+P were lower than for other treatments; The N concentrations for N and C+N+P were higher than for other treatments; The P concentrations for P and C+N+P were higher than for other treatments; and the effect of C+N+P on litter decomposition rate was significant higher than these of C, N and P, separately. The effects of different treatments on litter mass loss were differences and decomposition models showed the fast-slow-fast tendency.(4) The effect of carbon, nitrogen and phosphorus additions on litter decomposition could be reflected by the diversity of microbial groups and soil key enzyme activities under the litters. C improved the surcase activity when litters were decomposed after 180 days and 540 days, and improved the acid phosphatase activity after the decomposition of 180 days; N improved the acid phosphatase activity at the period of 180 days, while P improved the acid phosphatase activity at the period of 540 days.In conclusion, the responses of litter decomposition to carbon, nitrogen and phosphorus additions were complicated, and varied with tree species. The nutrient return through litter decomposition with C, N and P alteration need be further studied in forest ecosystems of mid-subtropical region, China.【关键词】凋落叶分解 网袋法 质量衰减 碳氮磷浓度 酶活性 微生物含量【英文关键词】Litter decomposition Bag incubation method Mass loss CNP concentration Enzyme activity Microbial biomass【目录】中亚热带四种树种凋落叶分解对碳氮磷调控的响应摘要3-5ABSTRACT5-6第1章 文献综述10-171.1 凋落物分解及养分释放过程10-111.2 凋落物分解的影响因素11-121.3 研究凋落物对碳调控响应的必要性121.4 研究凋落物对氮调控响应的必要性12-141.4.1 氮沉降对凋落物分解的影响12-131.4.2 营养元素氮对化学计量比的影响13-141.5 研究凋落物对磷调控响应的必要性141.6 小结与展望14-151.7 研究目的和意义151.7.1 课题来源151.7.2 研究目的151.7.3 研究意义151.8 研究内容15-161.9 拟解决的关键问题及本实验的新颖之处16-17第2章 试验样地与研究方法17-222.1 研究区概况与气候特征172.2 样地的选择17-182.2.1 研究样地的选择172.2.2 研究样地土壤理化性质17-182.3 试验设计18-212.3.1 试验设计18-202.3.2 研究方法20-212.4 技术路线212.5 数据处理与统计方法21-22第3章 氮磷添加对红壤区城郊湿地松林凋落叶分解的影响22-293.1 前言223.2 研究区概况和研究方法22-233.2.1 研究区概况223.2.2 研究样地223.2.3 试验设计与研究方法223.2.4 数据统计与研究方法22-233.3 结果与分析23-283.3.1 凋落叶分解过程重量衰减规律23-243.3.2 凋落叶分解过程养分浓度变化24-253.3.3 凋落叶分解过程养分释放规律25-263.3.4 不同分解时期凋落叶C、N、P化学计量比及其与分解速率的关系26-283.4 小结28-29第4章 马尾松林和常绿阔叶林主要树种凋落叶分解对碳氮磷调控的响应29-394.1 前言294.2 研究区与研究区概况29-304.2.1 研究区概况294.2.2 研究样地294.2.3 试验设计与研究