On the occasion of its twenty-fifth anniversary, in 1985, the Netherlands Society for Grassland and Fodder Crops (NVWV) agreed to organize an International Symposium on a topic related to intensive grass and fodder production systems. The theme selected was "Animal manure on grassland and fodder crops: Fertilizer or waste?" This Symposium was organized under the auspices of the European Grassland Federation and held at the International Agricultural Centre in Wageningen from 31 August to 3 September 1987. The problems connected with the disposal of animal waste have received much attention in recent years, especially in regions with intensive animal of animal manure per hectare agricul husbandry. Whereas the production tural land increased strongly, the need for it decreased because of the introduction of cheap inorganic fertilizers which are easier to handle and have a more reliable effect on crop growth. As a consequence, many farmers dispose of animal manure as cheaply as possible, whilst avoiding damage to grassland and crops and paying little attention to effective use of the plants nutrients contained in the manure. Present practices of manure handling and application often lead to environmental problems. The rise in awareness of these problems renewed interest in possibilities to improve the utilization of nutrients from animal manure in crop production. Research on this topic has been stimulated in many countries during the last decade and the aim of this Symposium was to review and assess present-day knowledge.