To calculate bulk density, simply weigh the sample and divide its mass by its volume. Bulk density is commonly used when referring to solid mixtures like soil. Just like particle density, bulk density is also measured in mass per volume.
Bulk density is useful for determining the density of a mixture that has many different compounds and elements in it. It is the simplest way to represent a mixture that has solid, liquid and gaseous components. Soil contains dirt, minerals, air and moisture and is usually rated based on bulk density. There are ideal levels of bulk density for optimum growing conditions.