DISSERTATION RESEARCH:Will CO2-mediated Increases in Fine-root Litter Progressively Decrease Forest N Availability by Increasing N Immobilization in Soil Organic Matter?

论文研究：二氧化碳介导的细根凋落物的增加是否会通过增加土壤有机质中的氮固定来逐渐降低森林氮的可用性？

• 批准号: 0708978
• 负责人: Richard Norby
• 金额: $ 1.17万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2009-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0708978&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Will; CO2; mediated

Soils have the capacity to store carbon for a long time. The degree to which plant remains are protected from decomposition in the soil profile will determine the amount of carbon and nitrogen stored in soils in response to rising atmospheric concentrations of carbon dioxide. The objective of this research is to mechanistically link the decomposition of fine-root litter to carbon and nitrogen immobilization in soil organic matter. Fine roots and soil organic matter with a depleted carbon-13 isotope signature will be taken from a CO2-enrichment experiment in a deciduous forest stand and decomposed in a reciprocal transplant experiment. Carbon from the decomposing fine roots will be quantified as it is transferred to fractions of soil organic matter with different longevities. Results of this project will advance the understanding of terrestrial processes that regulate above- and belowground carbon storage in forested ecosystems, and inform models used to predict ecosystem responses to climatic change.

土壤具有长期储存碳的能力。植物遗骸在土壤剖面中防止分解的程度将决定土壤中储存的碳和氮的数量，以应对大气中二氧化碳浓度的上升。这项研究的目的是将细根凋落物的分解与土壤有机质中碳和氮的固定联系起来。细根和具有贫化碳-13同位素特征的土壤有机质将从落叶林中的二氧化碳富集性实验中提取，并在相互移植实验中分解。分解的细根中的碳将被量化，因为它被转移到不同寿命的土壤有机质部分。该项目的成果将促进对调节森林生态系统地上和地下碳储量的陆地过程的理解，并为用于预测生态系统对气候变化的反应的模型提供信息。