Evaluation of potentially labile soil organic carbon and nitrogen fractionation procedures

► NaI and SPT density solutions were compared in recovering FLF organic matter. ► These solutions had the same efficiency in recovering FLF for the densities tested. ► For both chemical solutions the density of 1.8 g cm−3 resulted in less variation. ► SOM fractions were tested as sensitive indices due to change in tillage management. ► POM and OLF detected changes in organic C and N, while FLF did not.