ABSTRACT
The set of indices to be determined for the humus status of soils may vary depending on the purpose of a particular investigation. The processes of desertification and of soil salinisation lead to modification of the humus status of soils. The effect of chemical amelioration and chemical fertilisers on the humus status of soils is interesting not only from purely agronomic considerations, but also because it enables us to trace processes taking place during change in the ionic and salt composition of the soil solution and its reaction (pH). Chemical ameliorants significantly change the chemical condition of soils. In the first place they directly influence the oxidation-reduction regime, soil reaction and cation composition of the soil solution, and as a consequence the mobility of humus. Powdered limestone as also phospho-gypsum affected the extraction of humic substances with water but insignificantly changed the yield of humic acids and fulvic acids in the alkali extract compared to control.
