Soil organic carbon is significantly associated with the pore geometry, microbial diversity and enzyme activity of the macro-aggregates under different land uses

Ranjan Bhattacharyya*, Sheikh M.F. Rabbi, Yaqi Zhang, Iain M. Young, Andrew R. Jones, Paul G. Dennis, Neal W. Menzies, Peter M. Kopittke, Ram C. Dalal

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

Microbial activity strongly influences the stabilization of soil organic matter (SOM), and is affected by the abiotic properties within soil aggregates, which tend to differ between land uses. Here, we assessed the effects of SOM and pore geometry on the diversity and activity of microbial communities within aggregates formed under different land uses (undisturbed, plantation, pasture, and cropping). X-ray micro-computed tomography (μCT) revealed that macro-aggregates (2–8 mm) of undisturbed soils were porous, highly-connected, and had 200% more macro-pores compared with those from pasture and cropping soils. While the macro-aggregates of undisturbed soils had greater soil organic carbon (SOC) contents and N-acetyl β-glucosaminidase, β-glucosidase, and phosphatase activities, those of cropped soils harboured more diverse bacterial communities. Organic carbon was positively associated with the porosity of the macro-aggregates, which was negatively associated with microbial diversity and positively associated with enzyme activity. Thus, the biophysical processes in macro-aggregates may be important for SOC stabilization within the macro-aggregates.

Original languageEnglish (US)
Article number146286
JournalScience of The Total Environment
Volume778
DOIs
StatePublished - Jul 15 2021

Bibliographical note

Funding Information:
The first author thanks the Indian National Science Academy (INSA) for financial support received through the Early- and Mid- Career Researchers' Fellowship (2017-18). He also thanks the Head, Center for Environment Science and Climate Resilient Agriculture and the Joint Director Research, Indian Agricultural Research Institute, New Delhi for their kind support.

Publisher Copyright:
© 2021

Keywords

  • Bacterial diversity
  • Connectivity
  • Enzymes
  • Land use
  • Organic carbon
  • Porosity
  • Soil aggregates
  • Tomography

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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