This paper describes what has been achieved with ureaform fertilizer during the last twenty years. The knowledge about the agronomic value has increased and because of this it has been possible to adapt the product more to the needs of many horticultural crops. This has led to an increase of the activity index of good quality commercial ureaforms while total nitrogen content and cold-water insoluble nitrogen (WIN) were kept constant.

A comparison between the nitrogen release of good quality ureaform and the nitrogen needs of two horticultural crops (chrysanthemums and tomatoes) is made.

In the near future, the authors expect that it will be technologically possible to increase the activity index even further (with constant total nitrogen and WIN) which may render the product even more useful in a large variety of intensive horticultural crops.

H Schneider, Saarbergwerke AG, Saarbrucken, Germany
L Veegans, Hercules BV, The Hague, Netherlands

45 pages, 8 figures14 tables, 21 refs.