A Comparison of Physical Soil Organic Matter Fractionation Methods for Amended Soils

Table 3

Fractions obtained in each method as categorised by stabilisation mechanism: physically protected, chemically protected, or unprotected OM. Nomeclature provided by the original publications.

Physical fractionation method
Stabilisation mechanism	Plaza et al. [18] (PL)	Six et al. [9] density (SD)	Six et al. [9] microaggregate isolator (SMI)	Sohi et al. [19] (SO)	Zimmermann et al. [15] (ZM)
Unprotected	(i) Free OM (fOM)	(i) Free POM within large and small macroaggregates (lM fPOM and sM fPOM)	(i) Large POM/Litter >2000 μm (>2000POM)	(i) Free light OM (FLF)	(i) Particulate organic matter (POM)
	(ii) Intramacroaggregate OM (i-MaOM)		(ii) Coarse POM in large and small macroaggregates (lM cPOM and sM cPOM)		(ii) Dissolved organic C (DOC)
	(iii) Dissolved OM (DOM)
Physical	(i) Intramicroaggregate OM (i-miOM)	(i) Free POM within microaggregates (m fPOM)	(i) Intramicroaggregate POM (imPOM)	(i) Intraaggregate light OM (iAFLF)	(i) Sand and stable aggregates (S + A)
		(ii) Free POM in microaggregates within large and small macroaggregates (mlM fPOM and msM fPOM)	(ii) Intramicroaggregate POM within large and small macroaggregates (imlM POM and imsM POM)
Chemical	(i) Mineral-associated (MinOM)	(i) Mineral-associated SOC within large and small macroaggregates (lM mSOC and sM mSOC)	(i) Silt and clay (s + c)	(i) Mineral-associated OM (MA)	(i) Silt and clay (s + c)
		(ii) Mineral-associated SOC within microaggregates (m mSOC)	(ii) Silt and clay within large and small macroaggregates (lM s + c and sM s + c)		(ii) Resistant soil organic C (rSOC)
		(iii) Silt and clay (s + c)	(iii) Silt and clay within microaggregates (m s + c)