- Soil mapping and soil information, Digital soil mapping, Soil carbon
- Tropical soils and tropical agriculture
- Soil fertility and global soil science
- Soil publications and soil science history
- Co-initiator and coordinator of GlobalSoilMap (new soil map of the world).
- More than 200 publications, 10 books
- Invited and keynote speaker at soil and other conferences all over the world
- Secretary General, International Union of Soil Sciences