气候变化领域集成服务门户(CCPortal): Plant and soil responses of an alpine steppe on the Tibetan Plateau to multi-level nitrogen addition

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DOI	10.1007/s11104-013-1814-x
	Plant and soil responses of an alpine steppe on the Tibetan Plateau to multi-level nitrogen addition
	Liu, Yongwen; Xu-Ri; Xu, Xingliang; Wei, Da; Wang, Yinghong; Wang, Yuesi
通讯作者	Xu-Ri (通讯作者)
发表日期	2013
ISSN	0032-079X
EISSN	1573-5036
起始页码	515
结束页码	529
卷号	373 期号:1-2
英文摘要	Although plant growth in alpine steppes on the Tibetan Plateau has been suggested to be sensitive to nitrogen (N) addition, the N limitation conditions of alpine steppes remain uncertain. After 2 years of fertilization with NH4NO3 at six rates (0, 10, 20, 40, 80 and 160 kg N ha(-1) yr(-1)), the responses of plant and soil parameters as well as N2O fluxes were measured. At the vegetation level, N addition resulted in an increase in the aboveground N pool from 0.5 +/- 0.1 g m(-2) in the control plots to 1.9 +/- 0.2 g m(-2) in the plots at the highest N input rate. The aboveground C pool, biomass N concentration, foliar delta N-15, soil NO3 (-)-N and N2O flux were also increased by N addition. However, as the N fertilization rate increased from 10 kg N ha(-1) yr(-1) to 160 kg N ha(-1) yr(-1), the N-use efficiency decreased from 12.3 +/- 4.6 kg C kg N-1 to 1.6 +/- 0.2 kg C kg N-1, and the N-uptake efficiency decreased from 43.2 +/- 9.7 % to 9.1 +/- 1.1 %. Biomass N:P ratios increased from 14.4 +/- 2.6 in the control plots to 20.5 +/- 0.8 in the plots with the highest N input rate. Biomass N:P ratios, N-uptake efficiency and N-use efficiency flattened out at 40 kg N ha(-1) yr(-1). Above this level, soil NO3 (-)-N began to accumulate. The seasonal average N2O flux of growing season nonlinearly increased with increased N fertilization rate and linearly increased with the weighted average foliar delta N-15. At the species level, N uptake responses to relative N availability were species-specific. Biomass N concentration of seven out of the eight non-legume species increased significantly with N fertilization rates, while Kobresia macrantha and the one legume species (Oxytropics glacialis) remained stable. Both the non-legume and the legume species showed significant N-15 enrichment with increasing N fertilization rate. All non-legume species showed significant increased N:P ratios with increased N fertilization rate, but not the legume species. Our findings suggest that the Tibetan alpine steppes might be N-saturated above a critical N load of 40 kg N ha(-1) yr(-1). For the entire Tibetan Plateau (ca. 2.57 million km(2)), a low N deposition rate (10 kg N ha(-1) yr(-1)) could enhance plant growth, and stimulate aboveground N and C storage by at least 1.1 +/- 0.3 Tg N yr(-1) and 31.5 +/- 11.8 Tg C yr(-1), respectively. The non-legume species was N-limited, but the legume species was not limited by N.
关键词	EXTENSIVELY MANAGED GRASSLAND EVEREST ICE CORE NATURAL-ABUNDANCE NUTRIENT RESORPTION AMMONIUM RECORD CRITICAL LOADS N-2 FIXATION NE BAVARIA N/P RATIO DEPOSITION
英文关键词	N:P stoichiometry; Nisotope fractionation; N limitation; N saturation; N-use efficiency; N-uptake efficiency
语种	英语
WOS研究方向	Agriculture ; Plant Sciences
WOS类目	Agronomy ; Plant Sciences ; Soil Science
WOS记录号	WOS:000327400400035
来源期刊	PLANT AND SOIL
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258162
推荐引用方式 GB/T 7714	Liu, Yongwen,Xu-Ri,Xu, Xingliang,et al. Plant and soil responses of an alpine steppe on the Tibetan Plateau to multi-level nitrogen addition[J]. 中国科学院青藏高原研究所,2013,373(1-2).
APA	Liu, Yongwen,Xu-Ri,Xu, Xingliang,Wei, Da,Wang, Yinghong,&Wang, Yuesi.(2013).Plant and soil responses of an alpine steppe on the Tibetan Plateau to multi-level nitrogen addition.PLANT AND SOIL,373(1-2).
MLA	Liu, Yongwen,et al."Plant and soil responses of an alpine steppe on the Tibetan Plateau to multi-level nitrogen addition".PLANT AND SOIL 373.1-2(2013).