Exactly 35 years after the first Colloquium was held, the Eleventh International Plant Nutrition Colloquium took place from 30 July to 4 August 1989 in Wageningen, The Netherlands. Although impressive progress has been made during the past decades in our understanding of the mechanisms of uptake, distribution and assimilation of nutrients in relation to crop yield and quality, there are still significant gaps in our insight into many fundamental aspects of plant mineral nutrition and related metabolic processes. In spite of improved knowledge of nutrient requirements of crops and improved fertilizer application strategies, the world population remains to be burdened with an enormous shortage of plant products for food, timber, fuel, shelter, and other purposes. The main challenge facing the plant nutrition research community is to at least alleviate the increasing world-wide need for applying scientific knowledge to practical problems in agriculture, horticulture, and forestry. It is therefore felt by many scientists that the Plant Nutrition Colloquia, which are intended to bring together scientists and to integrate knowledge and approaches acquired in plant physiology, biochemis try, soil science, agronomy and related disciplines, have indeed made a significant contribution to the advancement of our knowledge and understanding in this vital and interdisciplinary field of agrobiology. About 260 scientists from 40 nations attended the Colloquium in Wageningen.