SG (Slot)

Basic physical properties including density, total
porosity, water capacity, differential porosity, air
permeability.
Samples for investigations were taken in all cases in
the beginning of June. In field cultivations, samples were
taken from fields under winter cereals when a natural
compaction of soil occurred throughout the winter and spring
season. To determine physical properties, samples of
natural structure were taken into barrels of 100 cm 3
capacity.
The obtained results were statistically analyzed by
means of non-ortogonal cross classification. For a
statistical comparison in case of forest soils, the results
from the levels whose depth responded to the analyzed layers
of arable soils were taken for analysis.
The present communique contains the results of density
determination (Tab. 2-4) and their short discussion.
Complete results of the investigations will be presented for
publication in Soil Tillage Research Journal.
RESULTS
In all the investigated arable soils, a significantly
higher density of 0-20 em layer was obtained in comparison
to the density of the respective layers of forest soils.
In the brown soil made of loess, as well as in the lessive
soil made of light clay there was also a differentiation of
compaction in the range of arable soils resulting from many
years compaction with heavy mechanical equipment. This
influence was noted not only in the surface layer but in the
skimmed layer as well. In both soils mentioned above,
density of the skimmed layer on fields compacted for many
years was significantly higher than on the fields where
tillage and other agrotechnical measures were applied with
the use of horses as tractive po,/er. The obtained results
of density determination, as well as of other soil features
prove that the introduction of full mechanization of field
work with heavy tractors and machines leads to degradation
of structure and physical properties of soil.
The size and scope of the influence of various ways of
agricultural utilization of soils on their structure and
physical properties depend on the character of soil material
humus content and the natural structure, as well as on soil
deformability.
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