Using metabolic tracer techniques to assess the impact of tillage and straw management on microbial carbon use efficiency in soil

Kees Jan Van Groenigen, Dermot Forristal, Mike Jones, Niamh Smyth, Egbert Schwartz, Bruce A Hungate, Paul Dijkstra

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Tillage practices and straw management can affect soil microbial activities with consequences for soil organic carbon (C) dynamics. Microorganisms metabolize soil organic C and in doing so gain energy and building blocks for biosynthesis, and release CO2 to the atmosphere. Insight into the response of microbial metabolic processes and C use efficiency (CUE; microbial C produced per substrate C utilized) to management practices may therefore help to predict long term changes in soil C stocks. In this study, we assessed the effects of reduced (RT) and conventional tillage (CT) on the microbial central C metabolic network, using soil samples from a 12-year-old field experiment in an Irish winter wheat cropping system. Straw was removed from half of the RT and CT plots after harvest or incorporated into the soil in the other half, resulting in four treatment combinations. We added 1-13C and 2,3-13C pyruvate and 1-13C and U-13C glucose as metabolic tracer isotopomers to composite soil samples taken at two depths (0-15cm and 15-30cm) from each of the treatments and used the rate of position-specific respired 13CO2 to parameterize a metabolic model. Model outcomes were then used to calculate CUE of the microbial community. Whereas the composite samples differed in CUE, the changes were small, with values ranging between 0.757 and 0.783 across treatments and soil depth. Increases in CUE were associated with a reduced tricarboxylic acid cycle and reductive pentose phosphate pathway activity and increased consumption of metabolic intermediates for biosynthesis. Our results suggest that RT and straw incorporation do not substantially affect CUE.

Original languageEnglish (US)
Pages (from-to)139-145
Number of pages7
JournalSoil Biology and Biochemistry
Volume66
DOIs
StatePublished - Nov 2013

Fingerprint

straw
tillage
tracer techniques
Soil
Carbon
tracer
conventional tillage
carbon
soil sampling
biosynthesis
soil
pentoses
tricarboxylic acid cycle
soil microorganisms
organic soils
soil organic carbon
microbial activity
soil depth
winter wheat
microbial communities

Keywords

  • Carbon
  • Carbon use efficiency
  • Glycolysis
  • Metabolic tracer probing
  • Pentose phosphate pathway
  • Soil microbial biomass
  • Stable isotopes
  • TCA cycle
  • Tillage

ASJC Scopus subject areas

  • Soil Science
  • Microbiology

Cite this

Using metabolic tracer techniques to assess the impact of tillage and straw management on microbial carbon use efficiency in soil. / Van Groenigen, Kees Jan; Forristal, Dermot; Jones, Mike; Smyth, Niamh; Schwartz, Egbert; Hungate, Bruce A; Dijkstra, Paul.

In: Soil Biology and Biochemistry, Vol. 66, 11.2013, p. 139-145.

Research output: Contribution to journalArticle

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