Regulating the Tempo of Nitrogen Turnover in Soils: Microbial and

调节土壤中氮素周转的速度：微生物和

• 批准号: 0616629
• 负责人: David Myrold
• 金额: --
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0616629&HistoricalAwards=false
• 关键词: Regulating; Tempo; Nitrogen; Turnover; Soils

Nitrogen is the nutrient that limits plant growth in most terrestrial ecosystems, but in some cases excess nitrogen can have negative environmental impacts. Past work has emphasized inorganic forms of nitrogen; however, in many ecosystems dissolved organic nitrogen is a larger pool. Relatively little is known about the rates of production and consumption of the dissolved organic nitrogen pool. This study will develop and test a new method to study the dynamics of dissolved organic nitrogen in soil. The method is a modification of the "isotope dilution" technique commonly used to study the turnover of inorganic soil nitrogen pools. The new method will produce dissolved organic nitrogen that is labeled with a stable isotope (15N). The labeled dissolved organic nitrogen will be added to soil to follow its consumption, by tracing the label into other nitrogen pools, and production, by measuring the dilution of the added (labeled) dissolved organic nitrogen as it is replaced by unlabeled dissolved organic nitrogen formed by natural microbial activity. If successful, this new application of the isotope dilution approach will provide a powerful tool for ecosystem scientists to study an important, but poorly understood aspect of the nitrogen cycle. It will have applications to both natural and managed ecosystems. More broadly, the insights that may be provided by the use of this approach may enable us to enhance plant productivity while minimizing detrimental environmental effects.

氮是大多数陆地生态系统中限制植物生长的营养素，但在某些情况下，过量的氮会对环境产生负面影响。过去的工作强调氮的无机形式;然而，在许多生态系统中，溶解的有机氮是一个更大的池。关于溶解有机氮库的产生和消耗速率，人们所知相对较少。本研究将开发和测试一种新的方法来研究溶解性有机氮在土壤中的动态。该方法是一个修改的“同位素稀释”技术通常用于研究无机土壤氮库的周转。新方法将产生用稳定同位素（15 N）标记的溶解有机氮。将标记的溶解有机氮添加到土壤中，通过将标记追踪到其他氮库中来跟踪其消耗，并通过测量添加的（标记的）溶解有机氮的稀释度来跟踪其生产，因为它被天然微生物活性形成的未标记的溶解有机氮所取代。 如果成功的话，这种同位素稀释方法的新应用将为生态系统科学家研究氮循环的一个重要但知之甚少的方面提供一个强大的工具。它将应用于自然和管理的生态系统。更广泛地说，通过使用这种方法可以提供的见解可以使我们能够提高工厂的生产力，同时最大限度地减少对环境的不利影响。