文献类型：期刊文献

英文题名：Non-Additive Effects of Water and Nitrogen Addition on Ecosystem Carbon Exchange in a Temperate Steppe

作者：Niu, Shuli[1] Yang, Haijun[1] Zhang, Zhe[1] Wu, Mingyu[1] Lu, Qi[2] Li, Linghao[1] Han, Xingguo[1] Wan, Shiqiang[1]

第一作者：Niu, Shuli

通信作者：Wan, SQ[1]

机构：[1]Chinese Acad Sci, Inst Bot, State Key Lab Vegetat & Environm Change, Beijing 100093, Peoples R China;[2]Chinese Acad Forestry, Res Inst Forestry, Beijing 100091, Peoples R China

年份：2009

卷号：12

期号：6

起止页码：915-926

外文期刊名：ECOSYSTEMS

收录：;Scopus(收录号：2-s2.0-70349675644);WOS:【SCI-EXPANDED(收录号:WOS:000270339300004)】；

基金：This study was conducted as part of a comprehensive research project (Global Change Multi-factor Experiment-Duolun) sponsored by the Institute of Botany, Chinese Academy of Sciences. The authors thank Zhiyou Yuan, Shihuan Song, Wenming Bai, and Xin Li for help in setting up the field facilities, Yi Han, Jianyang Xia, and Zhixiong Li for help in field measurements, and Shiping Chen for providing meteorological data. This study was financially supported by the National Natural Science Foundation of China (30870439, 30821062), Ministry of Science and Technology (2006BAD26B01), Chinese Academy of Sciences (Hundred Talents Program), and State Key Laboratory of Environmental and Vegetation Change.

语种：英文

外文关键词：carbon sequestration; ecosystem respiration; grassland; gross primary productivity; net ecosystem carbon exchange; precipitation regimes; nitrogen deposition; species composition

摘要：Changes in precipitation and nitrogen (N) deposition can influence ecosystem carbon (C) cycling and budget in terrestrial biomes, with consequent feedbacks to climate change. However, little is known about the main and interactive effects of water and N additions on net ecosystem C exchange (NEE). In a temperate steppe of northern China, a field-manipulated experiment was conducted to evaluate the responses of NEE and its components to improve N and water availability from 2005 to 2008. The results showed that both water and N additions stimulated gross ecosystem productivity (GEP), ecosystem respiration (ER), and NEE. Water addition increased GEP by 17%, ER by 24%, and NEE by 11% during the experimental period, whereas N addition increased GEP by 17%, ER by 16%, and NEE by 19%. The main effects of both water and N additions changed with time, with the strongest water stimulation in the dry year and a diminishing N stimulation over time. When water and N were added in combination, there were nonadditive effects of water and N on ecosystem C fluxes, which could be explained by the changes in species composition and the shifts of limiting resources from belowground (water or N) to above-ground (light). The positive water and N additions effects indicate that increasing precipitation and N deposition in the future will favor C sequestration in the temperate steppe. The non-additive effects of water and N on ecosystem C fluxes suggest that multifactor experiments are better able to capture complex interactive processes, thus improving model simulations and projections.