TECO: Collaborative Research: Immobilization of Nitrate in Temperature Forest Soils

TECO：合作研究：在温度森林土壤中固定硝酸盐

• 批准号: 9727057
• 负责人: Jon Chorover
• 金额: $ 28.2万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-15 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9727057&HistoricalAwards=false
• 关键词: TECO; Collaborative; Research; Immobilization; Nitrate

9727057 Hatcher One of the most subtle and pervasive aspects of human-induced global change is the chronic deposition of atmospheric nitrogen in the forests of the northeastern United States. The mechanisms by which inputs of inorganic nitrogen are converted to organic nitrogen and retained within the forest litter layer and mineral soil are key to understanding the fate of nitrogen from atmospheric deposition and its effects on carbon storage in forests. Currently, the processes by which inorganic nitrogen from atmospheric deposition is immobilized in soil are not understood. Whether or not organic nitrogen produced in soil is subsequently made available for plant growth or if it is stored in the soil-humus matrix are unknown. The "unknown nitrogen" fraction commonly comprises the largest single fraction of total soil nitrogen in conventional wet chemical analyses. This research will use 15N-nuclear magnetic resonance (NMR) technology to address these questions. Answers to these two fundamental questions are needed to fully comprehend the soil N cycle, and to predict the ultimate impact of chronic N deposition in forest ecosystems. This project will address these two fundamental questions by using existing long-term forest nitrogen addition experiments at Harvard Forest LTER site in Massachusetts, the Bear Brook Watershed in Maine, and the Fernow Experimental Forest in West Virginia.

9727057 Hatcher 人类引起的全球变化最微妙和最普遍的方面之一是美国东北部森林中大气氮的长期沉积。无机氮输入转化为有机氮并保留在森林凋落物层和矿质土壤中的机制是了解大气沉降中氮的归宿及其对森林碳储存影响的关键。目前，大气沉积中的无机氮固定在土壤中的过程尚不清楚。土壤中产生的有机氮是否随后可用于植物生长或是否储存在土壤腐殖质基质中尚不清楚。 “未知氮”部分通常包括传统湿化学分析中土壤总氮的最大单一部分。本研究将利用15N-核磁共振（NMR）技术来解决这些问题。需要回答这两个基本问题，才能充分理解土壤氮循环，并预测森林生态系统中长期氮沉降的最终影响。该项目将利用马萨诸塞州哈佛森林 LTER 站点、缅因州熊溪流域和西弗吉尼亚州弗诺实验森林现有的长期森林氮添加实验来解决这两个基本问题。