Selected activities of the Environmental Science and Technology Department during 1990 are presented. The research in the department is predominantly experimental, and the research topics emphaized are introduced and reviewed in eight chapters: 1. Introduction, 2. The Atmospheric Environment, 3. Plant Genetics and Biology, 4. Nutrient Efficiency in Plant Production, 5. Chemistry of the Geosphere, 6. Ecology and Mineral Cycling, 7. Other Acitvities, 8. Large Facilities. The department`s contribution to national and international collaborative research programmes is presented together with information about large facilities managed and used by the department as well as activities within education and training. Lists of scientific and technical staff members, visiting scientists, Ph.D. students, publications, lectures and poster presentations are included in the report. (author).