Skip to content

Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland

Research output: Contribution to journalArticle

Standard

Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland. / Turpin-Jelfs, Thomas; Michaelides, Katerina; Biederman, Joel A.; Anesio, Alexandre M.

In: Biogeosciences, Vol. 16, No. 2, 01.2019, p. 369-381.

Research output: Contribution to journalArticle

Harvard

APA

Vancouver

Author

Turpin-Jelfs, Thomas ; Michaelides, Katerina ; Biederman, Joel A. ; Anesio, Alexandre M. / Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland. In: Biogeosciences. 2019 ; Vol. 16, No. 2. pp. 369-381.

Bibtex

@article{3418a74afeba41b7bba3be5d55290fc6,
title = "Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland",
abstract = "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.",
author = "Thomas Turpin-Jelfs and Katerina Michaelides and Biederman, {Joel A.} and Anesio, {Alexandre M.}",
year = "2019",
month = "1",
doi = "10.5194/bg-16-369-2019",
language = "English",
volume = "16",
pages = "369--381",
journal = "Biogeosciences",
issn = "1726-4170",
publisher = "Copernicus GmbH",
number = "2",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Soil nitrogen response to shrub encroachment in a degrading semi-arid grassland

AU - Turpin-Jelfs, Thomas

AU - Michaelides, Katerina

AU - Biederman, Joel A.

AU - Anesio, Alexandre M.

PY - 2019/1

Y1 - 2019/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85060585802&partnerID=8YFLogxK

U2 - 10.5194/bg-16-369-2019

DO - 10.5194/bg-16-369-2019

M3 - Article

AN - SCOPUS:85060585802

VL - 16

SP - 369

EP - 381

JO - Biogeosciences

JF - Biogeosciences

SN - 1726-4170

IS - 2

ER -