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Role of dissolved organic nitrogen in the nitrogen cycle of a mountainous forest ecosytem in Taiwan

溶解有机氮在台湾山地森林生态系统氮循环中的作用

基本信息

批准号：
30000675
负责人：
Professor Dr. Egbert Matzner
金额：
--
依托单位：
Department of Natural Resources and Environmental Studies
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2009-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/30000675?language=en
关键词：
Role dissolved organic nitrogen cycle

项目摘要

Dissolved organic nitrogen (DON) plays a prominent role in the N cycle of forest soils under conditions of low N deposition and often represents the dominant form of N in solution. Little is known about the sources, properties, genesis and fate of DON, especially in subtropical forests under high precipitation regime. In field and laboratory studies we plan to investigate these issues in a mountainous Chamaecyparis obtusa var. formosana forest in Taiwan. In previous studies we found the fluxes of dissolved organic carbon (DOC) and DON exceptionally high in this ecosystem. Concentrations and fluxes of DON, DOC and mineral elements will be measured in fortnightly resolution in throughfall, forest floor percolates and seepage. The release and fate of DOC and DON in the soil will be related empirically to temperature, precipitation and throughfall chemistry. Different forest floor layers and decomposing roots will be investigated in laboratory extractions for their role as sources of DON and DOC. The quality of DON from different sources will be evaluated using C/N ratios and the composition of amino acids and amino sugars. In laboratory studies we will investigate the potential formation of DON by reaction of DOC with nitrite, using solutions that contain different qualities of dissolved organic matter. Furthermore, the microbial use and net mineralization of soil derived DON and DOC will be studied in laboratory incubations. Here we use samples from the field and from the laboratory experiments on DON formation by reaction of nitrite. The results are expected to substantially improve our understanding of the N cycle in these forest ecosystems.

在低氮沉降条件下，溶解有机氮（DON）在森林土壤的氮循环中起着重要作用，通常是氮在溶液中的主要形式。目前对DON的来源、性质、发生和归宿知之甚少，特别是在亚热带森林高降水条件下。在现场和实验室研究中，我们计划调查这些问题，在山区Chamaaparis obtusa变种。台湾的台湾森林。在以往的研究中，我们发现溶解有机碳（DOC）和DON的通量异常高，在这个生态系统。每两周测量一次穿透雨、森林地表水和渗漏中DON、DOC和矿物元素的浓度和通量。DOC和DON在土壤中的释放和命运将经验相关的温度，降水和穿透水化学。不同的森林地面层和分解的根将在实验室提取的DON和DOC的来源的作用进行了调查。利用C/N比值、氨基酸和氨基糖的组成对不同来源DON的质量进行评价。在实验室研究中，我们将调查DOC与亚硝酸盐反应形成DON的可能性，使用含有不同质量溶解有机物的溶液。此外，微生物的使用和净矿化的土壤来源的DON和DOC将在实验室培养研究。在这里，我们使用的样品，从现场和实验室实验DON形成的反应亚硝酸盐。预计这些结果将大大提高我们对这些森林生态系统中的N循环的理解。