干旱区生态环境知识资源中心(Arid): Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland

Arid

DOI	10.5194/bg-16-369-2019
	Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland
	Turpin-Jelfs, Thomas 1; Michaelides, Katerina 1,2; Biederman, Joel A.3; Anesio, Alexandre M.1,4
通讯作者	Turpin-Jelfs, Thomas
来源期刊	BIOGEOSCIENCES
ISSN	1726-4170
EISSN	1726-4189
出版年	2019
卷号	16 期号:2 页码:369-381
英文摘要	Transitions from grass-to shrub-dominated states in drylands by woody plant encroachment represent significant forms of land cover change with the potential to alter the spatial distribution and cycling of soil resources. Yet an understanding of how this phenomenon impacts the soil nitrogen pool, which is essential to primary production in arid and semi-arid systems, is poorly resolved. In this study, we quantified how the distribution and speciation of soil nitrogen, as well as rates of free-living biological nitrogen fixation, changed along a gradient of increasing mesquite (Prosopis velutina Woot.) cover in a semi-arid grassland of the southwestern US. Our results show that site-level concentrations of total nitrogen remain unchanged with increasing shrub cover as losses from inter-shrub areas (sum of grass and bare-soil cover) are proportional to increases in soils under shrub canopies. However, despite the similar carbon-to-nitrogen ratio and microbial biomass of soil from inter-shrub and shrub areas at each site, site-level concentrations of inorganic nitrogen increase with shrub cover due to the accumulation of ammonium and nitrate in soils beneath shrub canopies. Using the acetylene reduction assay technique, we found increasing ratios of inorganic nitrogen to bioavailable phosphorus inhibit rates of biological nitrogen fixation by free-living soil bacteria. Overall, these results provide a greater insight into how grassland-to-shrubland transitions influence the soil N pool through associated impacts on the soil microbial biomass.
类型	Article
语种	英语
国家	England ; USA ; Denmark
开放获取类型	Green Submitted, gold
收录类别	SCI-E
WOS记录号	WOS:000456710800004
WOS关键词	LITTER DECOMPOSITION ; WOODY ENCROACHMENT ; MICROBIAL BIOMASS ; VEGETATION CHANGE ; CARBON ; WATER ; PATTERNS ; IMPACTS ; ECOSYSTEMS ; INSIGHTS
WOS类目	Ecology ; Geosciences, Multidisciplinary
WOS研究方向	Environmental Sciences & Ecology ; Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/214604
作者单位	1.Univ Bristol, Sch Geog Sci, Bristol BS8 1SS, Avon, England; 2.Univ Calif Santa Barbara, Earth Res Inst, Santa Barbara, CA 93106 USA; 3.USDA, Southwest Watershed Res Ctr, Tucson, AZ USA; 4.Aarhus Univ, Dept Environm Sci, DK-4000 Roskilde, Denmark
推荐引用方式 GB/T 7714	Turpin-Jelfs, Thomas,Michaelides, Katerina,Biederman, Joel A.,et al. Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland[J],2019,16(2):369-381.
APA	Turpin-Jelfs, Thomas,Michaelides, Katerina,Biederman, Joel A.,&Anesio, Alexandre M..(2019).Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland.BIOGEOSCIENCES,16(2),369-381.
MLA	Turpin-Jelfs, Thomas,et al."Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland".BIOGEOSCIENCES 16.2(2019):369-381.