DNA-based determination of soil microbial biomass in alkaline and carbonaceous soils of semi-arid climate. (March 2018)

• Record Type: Journal Article
• Authors: Semenov, Mikhail; Blagodatskaya, Evgenia; Stepanov, Alexey; Kuzyakov, Yakov
• Is Part Of: Journal of arid environments. Volume 150(2018)
• Page Start: 54
• Page End: 61
• Publication Date: 2018-03
• Subjects: Alkaline soils -- Chloroform fumigation-extraction -- DNA quantification -- Land use -- Substrate-induced respiration; Arid regions ecology -- Periodicals; Arid regions -- Periodicals; Écologie des régions arides -- Périodiques; Régions arides -- Périodiques; 577.54
• DOI: 10.1016/j.jaridenv.2017.11.013
• Languages: English
• ISSNs: 0140-1963

Abstract

Abstract: The applicability of DNA-based analysis of soil microbial biomass was proven under conditions when the common approaches – chloroform fumigation-extraction (CFE) and substrate-induced respiration (SIR) – are restricted. These restrictions include certain soil properties typical for arid areas (alkaline or carbonaceous soils) or limitation by sample preparation (frozen samples). To prove the suitability and correspondence of the methods, microbial biomass was determined by CFE, SIR and by DNA quantification in slightly alkaline Chernozem and strongly alkaline Calcisol of semi-arid climate under contrasting land use. Quantification of double-stranded DNA (dsDNA) revealed an excellent agreement (R 2 = 0.96) with SIR-based microbial biomass (SIR-Cmic ) for soils with pH lower than 8. DNA- and CFE-based microbial biomass (CFE-Cmic ) correlated well (R 2 = 0.97) for all studied soils. The conversion factors from dsDNA to SIR-Cmic of 5.1 and to CFE-Cmic of 4.4 were obtained. In alkaline soils (pH > 8), microbial biomass measured by SIR was strongly underestimated because of CO2 retention in soil solution due to high pH and CO3 2− exchange with carbonates. Thus, the dsDNA quantification provides a simple and durable approach for microbial biomass analysis as alternative for SIR and CFE and can be successfully used in alkaline or calcareous semi-arid soils. Highlights: Microbial biomass is strongly underestimated by SIR in alkaline soils. Limited applicability of pH-based CO2 retention conversion factors. DNA-based microbial biomass is a valid alternative to SIR and CFE. The DNA-to-Cmic conversion factor is refined for soils of semi-arid climate. DNA-based eco-physiological indexes revealed positive effect of agrogenic impact.