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Cell Biology JoVE (Open Access) Citable · DOI

Combined Size and Density Fractionation of Soils for Investigations of Organo-Mineral Interactions

DOI: 10.3791/58927-v
What you'll learn
  • ✓ Perform combined size and density fractionation to separate soil components
  • ✓ Isolate soil fractions with different reactivities toward organic matter
  • ✓ Interpret organo-mineral interactions using fractionated soil samples
  • ✓ Assess soil organic matter dynamics across different soil horizons
Protocol

Combined size and density fractionation (CSDF) is a method to physically separate soil into fractions differing in texture (particle size) and mineralogy (density). The purpose is to isolate fractions with different reactivities towards soil organic matter (SOM), in order to better understand organo-mineral interactions and SOM dynamics.

Difficulty
intermediate
Total time
~4–6 hours per soil sample (including centrifugation and settling steps)

Steps

1
Separate light fraction from heavy soil material

Use sodium polytungstate solution to extract the light fraction (LF) via flotation, isolating less-dense organic and mineral particles from denser mineral soil components.

▶ 00:38
2
Fractionate heavy fractions by particle size

Separate the heavy fractions (hFs) into coarse and fine particles using sieving or sedimentation based on defined particle-size cutoffs.

▶ 04:13
3
Separate size fractions according to mineral density

Apply density-based separation to each size fraction using density gradient media to isolate mineral phases with different reactivities.

▶ 04:54
4
Analyze material distribution across soil fractions

Quantify and characterize the distribution of materials among fractions as a function of soil mineralogy and soil depth to understand organo-mineral associations.

▶ 06:31
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