Strickland, T. C.; Sollins, P. 1987. Improved method for separating light- and heavy-fraction organic material from soil. Soil Science Society of America Journal. 51(5): 1390-1393.
An improved method is presented for separating whole soil intoa mineral-free organic fraction (light fraction) and an organomineralfraction (heavy fraction) by flotation in a dense inorganic salt so-lution. In the existing method. the heavy fraction is settled by cen-trifugation and the light fraction decanted. In the improved method,the light fraction is aspirated from the solution surface by suctionafter the soil suspension is allowed to settle. The improved methodcosts less, is more reproducible, and is practical in coarse-texturedsoils where heavy fractions do not form stable pellets during cen-trifugation.
Additional Index Words: density fractionation, organic matter, C,N.