25 Oct 2022
25 Oct 2022
Status: this preprint is currently under review for the journal BG.

Technical note: The recovery rate of free particulate organic matter is strongly reduced by conventional density fractionation of soil samples

Frederick Büks Frederick Büks
  • Chair of Soil Science, Dept. of Ecology, Technische Universität Berlin, 10587 Berlin, Germany

Abstract. Ultrasonication combined with density fractionation (USD) is a method widely used to quantify soil organic matter pools. A selective fractionation of free particulate organic matter (fPOM) is crucial to avoid co-extraction of retained fPOM along with occluded particulate organic matter (oPOM). In the present work, artificial fPOM was extracted from two mineral matrices, sandy and loamy, after applying different approaches for merging sample and dense medium. It could be shown that pouring the dense solution to the mineral matrices leads to low recovery, whereas trickling the sample into the solution, rotating after fill-up or applying a minimal and defined amount of ultrasound to swirl up the sample causes nearly full recovery of the artificial fPOM. Applied to natural soils, the results confirmed the low extraction rate of the fill-up approach. Moreover, it was possible to show that the rotational approach results in only a slightly increased extraction rate, whereas the ultrasound approach leads to a release of oPOM into the fPOM fraction due to disruption of soil macro-aggregates. The trickle approach appears to be the most appropriate way among the tested methods to achieve complete and selective extraction of fPOM from natural soil samples.

Frederick Büks

Status: open (until 04 Jan 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Frederick Büks


Total article views: 172 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
135 32 5 172 10 1 2
  • HTML: 135
  • PDF: 32
  • XML: 5
  • Total: 172
  • Supplement: 10
  • BibTeX: 1
  • EndNote: 2
Views and downloads (calculated since 25 Oct 2022)
Cumulative views and downloads (calculated since 25 Oct 2022)

Viewed (geographical distribution)

Total article views: 180 (including HTML, PDF, and XML) Thereof 180 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 09 Dec 2022
Short summary
Ultrasonication with density fractionation of soils is a commonly used method to quantify soil organic matter pools, which is e.g. important to calculate carbon turnover in landcapes. It is shown, that the conventional approach of merging soil and dense solution has a low recovery rate and causes co-extraction of parts of the retained labile pool along with the intermediate pool. An alternative methode with high recovery rates and no cross-contamination was developed.