Chronic Nitrogen Additions to Forest Ecosystems: Effects on Nitrogen Cycling, Canopy Chemistry and Nitrous Oxide Emissions

拟议的研究将检查两种森林生态系统对硝酸铵长期添加的反应中氧化亚氮排放的变化。还将测量氮矿化和硝化作用，硝酸盐浸出，以及树叶和细根的生物量和化学含量的变化。这种测量组合的目的是增加我们对目前在许多温带森林地区发生的氮输入速率升高、这些森林中氮循环的速率和形式以及氮循环速率增加对区域氧化亚氮排放的影响之间关系的理解。另一个目标是发展排放与叶面生物量和化学之间的定量关系，这种关系可与新兴的遥感技术结合使用，以估计整个植被类型或区域上的Nz0通量。

The proposed research will examine changes in nitrous oxide emissions from two forest ecosystems in response to chronic additions of ammonium nitrate. Measurements will also be made of nitrogen mineralization and nitrification, nitrate leaching, and changes in the biomass and chemical content of foligage and fine roots. The purpose of this combination of measurements is to increase our understanding of the relationships between elevated rates of nitrogen inputs currently occurring in many temperate forest zones, the rate and form of nitrogen cycling in those forests, and the impact of increasing nitrogen cycling rates on regional emissions of nitrous oxide. An additional goal is to develop quantitative relationships between emissions and foliar biomass and chemistry which can be used in conjunction with emerging remote sensing technologies to estimate Nz0 flux over whole vegetation types or regions.