期刊
PLANT AND SOIL
卷 336, 期 1-2, 页码 433-441出版社
SPRINGER
DOI: 10.1007/s11104-010-0493-0
关键词
Elevated CO2; Progressive nitrogen limitation; Grassland
资金
- New Zealand Foundation for Research, Science and Technology
A decline in the availability of nitrogen (N) for plant growth (progressive nitrogen limitation or PNL) is a feedback that could constrain terrestrial ecosystem responses to elevated atmospheric CO2. Several long-term CO2 enrichment experiments have measured changes in plant and soil pools and fluxes consistent with PNL but evidence for PNL in grasslands is limited. In an 11 year Free Air CO2 Enrichment (FACE) experiment on grazed grassland we found the amount of N harvested in aboveground plant biomass was greater at elevated CO2 but declined over time to be indistinguishable from ambient after 5 years. Re-wetting after a major drought resulted in a large input of N from mineralisation and a return to a higher N harvested under elevated CO2 followed by a further decline. Over these two periods the amount of N in soil significantly increased at elevated CO2. Data from mesocosms introduced into the rings at intervals, and therefore having different lengths of exposure to CO2, showed plant N availability declined at elevated CO2 reaching a new equilibrium after 6 years of exposure. We conclude that the availability of N for plants in this grassland is dynamic but the underlying trend at elevated CO2 is for PNL.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据