Bulk density

Abstract

Bulk density varies with structural condition of the soil, particularly that related to packing. Bulk density is determined in excavation method by excavating a quantity of soil, drying and weighing it, and determining the volume of the excavation. The bulk density of clods, or coarse peds, can be calculated from their mass and volume. The volume may be determined by coating a clod of known weight with a water-repellent substance and by weighing it first in air, then again while immersed in a liquid of known density, making use of Archimedes’ principle. The transmission of gamma radiation through soil or scattering within soil varies with soil properties, including bulk density. Radiation methods have several advantages, among which are minimum disturbance of the soil, short time required for sampling, accessibility to subsoil measurement with minimum excavation, and the possibility of continuous or repeated measurements at the same point.