Changes in soil internal N cycle and trace gas fluxes under elevated nutrient input

养分输入增加下土壤内部氮循环和微量气体通量的变化

• 批准号: 36004393
• 负责人: Professor Dr. Edzo Veldkamp
• 金额: --
• 依托单位: Abteilung Ökopedologie der Tropen und Subtropen
• 依托单位国家: 德国
• 项目类别: Research Units
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/36004393?language=en
• 关键词: Changes; soil; internal; cycle; trace

Although projections are that N deposition will increase strongly in the tropics, its effects on tropical forests are still largely descriptive. In the proposed project we plan to continue on-going measurements of soil-atmosphere fluxes of N2O, NO, CH4 and CO2 (NUMEX experiment). Our early results suggest that after the first year of flux measurements there are already substantial changes in the microbial processes nitrification and denitrification. Furthermore there are indications that N cycling rates have increased in plots that receive N addition at moderate rates. We plan to conduct measurements using 15N pool dilution and a 15N pulse chase experiment to assess quantitatively how microbial N cycling has changed in forest soils and to translate the short-term N fluxes to long-term fates of NH4 + and NO3 - in forest soils exposed to chronic N addition. Another focus will be potential feedbacks of N deposition on the soil carbon cycling by measuring heterotrophic CO2 respiration. During the first phase, our group discovered in cooperation with A5 that tank bromeliads are a substantial source of Methane. We plan a series of measurement to determine the size of these CH4 emissions from different elevations.

尽管预计热带地区的氮沉积将大幅增加，但它对热带森林的影响在很大程度上仍是描述性的。在拟议的项目中，我们计划继续对土壤-大气中N2O、NO、CH4和CO2的通量进行测量(Numex实验)。我们的早期结果表明，在第一年的通量测量之后，微生物过程中的硝化和反硝化已经发生了实质性的变化。此外，有迹象表明，在中等施氮量的地块中，氮素循环速率有所增加。我们计划使用15N池稀释和15N脉冲追逐实验进行测量，以定量评估森林土壤中微生物N循环的变化，并将短期N通量转化为长期暴露在N添加下的森林土壤中NH4+和NO3-的命运。另一个焦点将是通过测量异养二氧化碳呼吸来研究氮沉积对土壤碳循环的潜在反馈作用。在第一阶段，我们的团队与A5合作发现，坦克菠萝是甲烷的重要来源。我们计划进行一系列测量，以确定不同海拔地区甲烷排放量的大小。