Use of 15N natural abundance in nitrogen cycling of terrestrial ecosystems
15N自然丰度法在陆地生态系统氮循环研究中的应用

Stable isotope technique has been widely used in ecology research with the increasing concern on global change.Our objectives are to better understand the impacts of nitrogen addition and other environment changes on the nitrogen cycling of terrestrial ecosystem,predict the consequent changes in environmental conditions,and provide a reference for policy making to help ensure the sustainable development of terrestrial ecosystems.Based on the relationship between nitrogen (N) isotope composition (δ15N) in ecosystem N status and soil N cycle,we summa-rized the effects and mechanisms of N input and other environment changes on δ15N of plant and soil.Most stud-ies show significant positive relationships between N input and δ15N values of plant and soil.Higher N input in-creases soil N availability,which leads to 15N enrichment in soil because of mass discrimination during soil N cycling processes.Foliar δ15N also will be higher as plants take up the relatively 15N-enriched soil available N.15N natural abundance can be a useful tool for assessing nitrogen saturation and N cycling.