Decomposition of soil organic matter as affected by clay types, pedogenic oxides and plant residue addition rates

Mandeep Singh, Binoy Sarkar, Nanthi S. Bolan, Yong Sik Ok, Gordon Jock Churchman

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


The interactive effects of the types and contents of soil clay fractions (SCFs) and plant-residue addition rates on soil organic carbon (SOC) stabilisation are largely unknown. We conducted incubation experiments by amending a sandy soil sample with kaolinitic-illitic, smectitic and allophanic SCFs and adding wheat residues to the mineral mixtures to compare their C stabilisation capacity. The rate of carbon (C) decomposition was higher in the kaolinitic-illitic SCF followed by smectitic and allophanic clay minerals. The supply of easily degradable C substrate from decomposing residues markedly influenced the SCFs’ abilities to stabilise SOC. The removal of sesquioxides from the SCFs significantly decreased their C stabilisation capacity, which coincided with a decrease in the dehydrogenase activity of the mineral-residue mixture. The allophanic SCF showed the least microbial activity and the greatest C stabilisation due to having a higher proportion of micropores (75%). The high C stabilisation capacity of allophanic SCF could also be explained by its high specific surface area (119 m2 g−1). The results of this study are helpful to understand the role of various SCFs in stabilising added C originating from external wheat residue addition but warrant further validation under field conditions.

Original languageEnglish
Pages (from-to)11-19
Number of pages9
JournalJournal of hazardous materials
Publication statusPublished - 2019 Jul 15

Bibliographical note

Publisher Copyright:
© 2019 Elsevier B.V.


  • Microbial activity
  • Organic carbon stabilisation
  • Respiration
  • Soil clay fractions
  • Wheat plant residue

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution
  • Health, Toxicology and Mutagenesis


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