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Comparison of fungal and bacterial growth after alleviating induced N-limitation in soil

Kamble, Pramod N. LU and Bååth, Erland LU (2016) In Soil Biology and Biochemistry 103. p.97-105
Abstract

The extent and type of nutrient limitation will affect soil microorganism activity and may change the balance between organism groups, like fungi and bacteria. Limiting nutrients have traditionally been measured as increased respiration after adding nutrients, but this will not differentiate between fungal or bacterial responses. We compared respiration, bacterial and fungal growth after alleviating limitation in soils originally being C-limited, but experimentally altered to N-limitation. Three soils of similar pH and organic matter but with different N availability were used. We amended the soils with C-rich substrates, starch (40 mg g−1) and straw (80 mg g−1), followed by a 4 weeks incubation at 22 °C to induce... (More)

The extent and type of nutrient limitation will affect soil microorganism activity and may change the balance between organism groups, like fungi and bacteria. Limiting nutrients have traditionally been measured as increased respiration after adding nutrients, but this will not differentiate between fungal or bacterial responses. We compared respiration, bacterial and fungal growth after alleviating limitation in soils originally being C-limited, but experimentally altered to N-limitation. Three soils of similar pH and organic matter but with different N availability were used. We amended the soils with C-rich substrates, starch (40 mg g−1) and straw (80 mg g−1), followed by a 4 weeks incubation at 22 °C to induce N-limitation. Starch amendment resulted in increased respiration and bacterial growth, while straw amendment increased all three variables (respiration, bacterial and fungal growth), with only minor differences between soils. Alleviating C- and N-limitation was then tested in a short-term assay after adding C (glucose) and NH4NO3 in a full factorial design. In non-amended, C-limited soils, adding C resulted in increased respiration and especially bacterial growth, while fungal growth only increased in the High N soil. Straw amendment resulted in N-limitation, since adding N increased respiration and especially fungal growth. N-limitation for bacterial growth was evident in all starch amended soils, with similar effects for respiration, although adding C also increased respiration. Fungal growth was not affected by C- or N-additions in starch-amended soils. Thus, which microbial group that responded to alleviating N-limitation depended on the C-source in the soil. Furthermore, we found no indication of growth and respiration reacting differently to alleviating N-limitation indicating altered C-use efficiency.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ac-in-erg, Bacterial growth, Fungal growth, Leucine, N-limitation, Respiration
in
Soil Biology and Biochemistry
volume
103
pages
9 pages
publisher
Elsevier
external identifiers
  • Scopus:84983387146
ISSN
0038-0717
DOI
10.1016/j.soilbio.2016.08.015
language
English
LU publication?
yes
id
f0a1db06-8062-42f7-8392-a17c53504cf3
date added to LUP
2016-10-12 13:31:12
date last changed
2016-10-12 13:31:12
@misc{f0a1db06-8062-42f7-8392-a17c53504cf3,
  abstract     = {<p>The extent and type of nutrient limitation will affect soil microorganism activity and may change the balance between organism groups, like fungi and bacteria. Limiting nutrients have traditionally been measured as increased respiration after adding nutrients, but this will not differentiate between fungal or bacterial responses. We compared respiration, bacterial and fungal growth after alleviating limitation in soils originally being C-limited, but experimentally altered to N-limitation. Three soils of similar pH and organic matter but with different N availability were used. We amended the soils with C-rich substrates, starch (40 mg g<sup>−1</sup>) and straw (80 mg g<sup>−1</sup>), followed by a 4 weeks incubation at 22 °C to induce N-limitation. Starch amendment resulted in increased respiration and bacterial growth, while straw amendment increased all three variables (respiration, bacterial and fungal growth), with only minor differences between soils. Alleviating C- and N-limitation was then tested in a short-term assay after adding C (glucose) and NH<sub>4</sub>NO<sub>3</sub> in a full factorial design. In non-amended, C-limited soils, adding C resulted in increased respiration and especially bacterial growth, while fungal growth only increased in the High N soil. Straw amendment resulted in N-limitation, since adding N increased respiration and especially fungal growth. N-limitation for bacterial growth was evident in all starch amended soils, with similar effects for respiration, although adding C also increased respiration. Fungal growth was not affected by C- or N-additions in starch-amended soils. Thus, which microbial group that responded to alleviating N-limitation depended on the C-source in the soil. Furthermore, we found no indication of growth and respiration reacting differently to alleviating N-limitation indicating altered C-use efficiency.</p>},
  author       = {Kamble, Pramod N. and Bååth, Erland},
  issn         = {0038-0717},
  keyword      = {Ac-in-erg,Bacterial growth,Fungal growth,Leucine,N-limitation,Respiration},
  language     = {eng},
  month        = {12},
  pages        = {97--105},
  publisher    = {ARRAY(0xb48b878)},
  series       = {Soil Biology and Biochemistry},
  title        = {Comparison of fungal and bacterial growth after alleviating induced N-limitation in soil},
  url          = {http://dx.doi.org/10.1016/j.soilbio.2016.08.015},
  volume       = {103},
  year         = {2016},
}