Summary: In the regions beyond the river Tisza investigations were carried out on connections between human activity and the salt dynamics of unirrigated alkali soils.

On the basis of the analysis of about 2000 soil samples the following could be stated:

1. The salt migration in the soils are determined by the precipitation, evaporation and groundwater level in concordance with each other and depending on the mechanical and chemical composition of the soil and also on the depth.

2. With a groundwater level about the „critical depth" the salt mobilizing effect of deep tillage, the subsoiling to the depth of 60 cm is more intensive than salt mobilizing effect of shallow tilling, the ploughing to 15 cm depth.

3. As to the effectivity the above factors are followed by chemical and physical amelioration (plastic foam). Their influence is restricted mainly on the layer envisaged to be ameliorated.

4. Chemical and physical amelioration increase the salt migration in the respective soil layer (on account of their structure-ameliorating effect) while the unameliorated soil will, in want of such effects exert a decreasing influence.

5. The physical ameliorating material – poly-stirol and poly uretan foams – will even contribute to the effect of the chemical factors.

6. The salt migration of the surface soil is determined – in accordance with its position – by the groundwater level situated in the zone above the „critical level" (in conformity with the precipitation and evaporation). With a high groundwater level the salt maximum is to be found higher and with a lower one lower.

7. Depending on the qualities of alkali soils their ameliorations is to be begun with subsoil work. The leaching of soulbe salt will be thus increased which greatly contribute to the amelioration of the soil.

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