Coring lubricants can increase soil microbial activity in Vertisols

Katherine Polain; Gabrielle Joice; Dominic Jones; Lily Pereg; Gunasekhar Nachimuthu; Oliver G G Knox

doi:10.1016/j.mimet.2019.105695

Coring lubricants can increase soil microbial activity in Vertisols

J Microbiol Methods. 2019 Oct:165:105695. doi: 10.1016/j.mimet.2019.105695. Epub 2019 Aug 20.

Authors

Katherine Polain¹, Gabrielle Joice², Dominic Jones³, Lily Pereg⁴, Gunasekhar Nachimuthu⁵, Oliver G G Knox⁴

Affiliations

¹ Faculty of Science, Agriculture, Business and Law, University of New England, Armidale, NSW 2350, Australia. Electronic address: kpolain2@une.edu.au.
² McCarthy Catholic College, North Tamworth, NSW 2340, Australia.
³ Oxley High School, Tamworth, NSW 2340, Australia.
⁴ Faculty of Science, Agriculture, Business and Law, University of New England, Armidale, NSW 2350, Australia.
⁵ NSW DPI, Locked bag 1000, Narrabri, NSW 2390, Australia.

PMID: 31442458
DOI: 10.1016/j.mimet.2019.105695

Abstract

It is essential that sampling procedures for biological measurements are done in a way that reflects the soil processes, whilst limiting sampling artefacts. In heavy clay Vertisol soils, coring lubricants are often considered necessary in order to extract and recover soil for quality and health assessments. Previous reports into the use of coring lubricants have found soil carbon measurements to be inflated but to date, a study to evaluate the effects of these lubricants on soil microbial activity, has not been forthcoming. We measured soil carbon dioxide (CO₂) evolution in response to the addition of common coring lubricants, to determine the effects upon soil microbial activity to the depth of 100 cm. Application of coring lubricants to the surface soil layers of field collected cores did not significantly influence CO₂ evolution however, microbial activity increased in deeper soil layers (30-100 cm) with the use of WD-40, mould stripper and silicone oil. When the ratio of coring lubricant to soil was increased to ~5 g coring lubricant to 100 g^-1 soil, there was a significant (P = .001) effect on microbial activity, with silicone oil and mould stripper inflating measurements by at least 5%, whilst olive oil and WD-40 were similar to the control. The results imply that when using coring rigs to recover soil for microbial functional analysis in Vertisols, the use of coring lubricants is best avoided, with further research recommended.

Keywords: Biological indicators; Soil microbial analysis; Soil sampling; Substrate induced respiration; Vertosol.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon Dioxide / analysis*
Clay / microbiology*
Lubricants / chemistry*
Soil / chemistry*
Soil Microbiology*

Substances

Lubricants
Soil
Carbon Dioxide
Clay