abstract: The present studies aimed at ascertaining whether it is possible to determine the basic properties of the whole mass of a mineral soil basing on several granulometric fractions isolated (provided that their quantitative relations are known).
Fourteen profiles of mineral soils were chosen from 3 regions of Poland (i.e. the Carpathians, the regions of Lublin and Warsaw), representing soils in various stages of their development and formed from various rocks. The studies on the whole mass of soil samples, as well as individual fractions isolated by means of physical methods, were carried out using methods accepted in our laboratories.
The study results have been presented in 47 tables and in 71 figures.
The most important conclusions drawn can be summarised as follows:

1. The studies confirmed that there are relations between some soil properties and their granulometric composition.
2. The mineralogical composition of the colloidal fractions (clay) <0.002 mm is quantitatively and qualitatively differentiated in individual groups of soils. The finest fraction is characterised by a quantitative increase of mixed-layer minerals.
3. Some of the physical features, such as bulk density, decrease in the sand fraction up to 0.005-0.002 mm, then increase.
4. The content of carbon in organic compounds and nitrogen in the granulometric fractions increases clearly with decreasing diameter, and gradually decreases in the same group of fractions with an increase of depth in the soil profile.
5. The content of the humic acids is predominant in the granulometric fractions with higher diameter, and their content gradually decreases with a decrease in the diameter fraction. Fulvic acids are dominant in the fractions of <0.002 mm, hence Kh:Kf relations gradually decrease in grains with decreasing diameter.
6. Solubility of the humic compounds increases gradually with the decreasing diameter of granulometric fractions, and the content of humin and ulmin in these compounds decreases.
7. The exchangeable sorption capacity increases with the decreasing diameter of granulometric fractions, especially the fraction <0.002 mm, in all the soils studied. Also the degree of saturation with basic cations in the same fractions increases with an increase of depth in the soil profile.
8. The dominant exchangeable cations in the granulometric fractions are calcium and hydrogen. In the coarser fractions, hydrogen is predominant in most soils and in finer ones – calcium.
9. The content of aluminium, iron, magnesium and phosphorus increases with diameter decrease of the granulometric fractions; this situation is reversed in the case of silica whereas potassium shows the highest content in the 0.005-0.002 mm fraction. No regularities are observed in the case of calcium.
10. Correlation coefficients between individual components in the groups of fractions are strongly differentiated from highly positive to highly negative.
11. On the basis of the granulometric composition determined, it is possible to determine some physical properties of the whole soil, such as volumetric density, solid phase, and total porosity. Similarly, it will be possible to undertake the establishing of the total content of some components in the soil such as, for example, SiO2, K2O and possibly also MgO.

keywords: granulometric fractions, fraction properties

original in: Polish