Physical-chemistry and technology of soils and clays; plant-soil relationships; the role of soils in the global planetary processes of Earth and the other planets.
Wastewater reclamation and reuse: Redox processes, effects on soil geochemistry.
Soil pollution by heavy metals; dynamics of trace-elements in soils.
Long-term soil deterioration processes, involving salinity and sodicity in arid-zones.
Surface acidity of clays and soils.
The soils of Mars.