Bulk density
In
Bulk density is useful for materials such as
Bulk density is not the same as the
Soil
The bulk density of soil depends greatly on the mineral make up of soil and the degree of compaction.[3] The density of quartz is around 2.65 g/cm3 but the (dry) bulk density of a mineral soil is normally about half that density, between 1.0 and 1.6 g/cm3. In contrast, soils rich in soil organic carbon and some friable clays tend to have lower bulk densities (<1.0 g/cm3) due to a combination of the low-density of the organic materials themselves and increased porosity. For instance, peat soils have bulk densities from 0.02 to 0.98 g/cm3.[4] In a detailed study which has used 6,000 analysed samples in the European Union, a high resolution map (100m) of soil bulk density for the 0-20cm using regression model.[5] Croplands have almost 1.5 times higher bulk density compared to woodlands.
Bulk density of soil is usually determined from a core sample which is taken by driving a metal corer into the soil at the desired depth and horizon.[6] This gives a soil sample of known total volume, Vt. From this sample the wet bulk density and the dry bulk density can be determined.[7]
For the wet bulk density (total bulk density) this sample is weighed, giving the mass Mt. For the dry bulk density, the sample is oven dried and weighed, giving the mass of soil solids, Ms. The relationship between these two masses is Mt = Ms + Ml, where Ml is the mass of substances lost on oven drying (often, mostly water). The dry and wet bulk densities are calculated as
Dry bulk density = mass of soil/ volume as a whole
Wet bulk density = mass of soil plus liquids/ volume as a whole
The dry bulk density of a soil is
See also
- Brazil nut effect
- Characterisation of pore space in soil
- Effective porosity
- Density meter
- Number density
Notes
- ^ Buckman, Harry O.; Brady, Nyle C. (1960). The Nature and Property of Soils - A College Text of Edaphology (6th ed.). New York City: Macmillan. p. 50.
- ^ "Powder Bulk Density - Bulk Solids density - Bulk Powder Properties - Powder Loose Density - Powder tapped density - PowderProcess.net". www.powderprocess.net. Retrieved 2018-02-22.
- ^ Soil compaction impact and modelling. A review
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- ^ USDA Natural Resources Conservation Service "Soil quality indicators -- Bulk density" Archived 2020-04-13 at the Wayback Machine retrieved December 5, 2013
- ^ Argonne National Lab "RESRAD Data collection handbook, chapter 2 -- Soil density" retrieved May 26, 2012 Archived September 15, 2016, at the Wayback Machine