Simple Modification of the Clod Method for Determining Bulk Density of Very Gravelly Soils

Abstract

The accuracy of the clod method in determining fine‐earth bulk density in very gravelly soils can be affected by the difficulty of fine‐earth separation from both coarse fragments and the coating substance. A modification of the paraffin‐coated clod method is presented that accurately determines fine‐earth bulk density of very gravelly soils. The modification involves washing the paraffin‐coated clod in boiling water to separate paraffin from gravel and hardened soil aggregates. Samples were analyzed with an existing gravel correction method, herein referred to as the hand removal method (HRM), and the proposed modification, which is named the gravel washing method (GWM). Bulk density means for HRM and GWM were 1.29 and 1.41 g cm⁻³, respectively. This trend of higher bulk densities for GWM was consistent across pedons sampled in the study and was attributed to its ability to completely remove wax from gravels and hardened soil aggregates, effectively separating the fine‐earth fraction.

Keywords:

• Soil density
• volumetric analyses
• coarse fragments