Geoscience Reference
In-Depth Information
Fig. 7.5
The size and position of an experimentally measured soil sample should provide identical
estimates of porosity
P
for the representative elementary volume
REV
of the soil
simple task. A special glass container with a glass plug, called a pycnometer, is
fi lled with water and weighed. Next, after a known weight of the dried soil is placed
into the pycnometer, it is fi lled to its capacity with water and weighed again.
From the fi rst and second measured weights, we obtain the particle density,
which is about 2.6 g/cm
3
in the majority of topsoils containing signifi cant quantities
of humus. Soils from deeper horizons without humus have slightly higher
