Keywords: Nitrate in vegetables, Nitrate and health, Vegetable fertilizers.

CONCLUSIONS:
It can be summarised that the same strategies which were developed to avoid nitrate leaching are suitable to reduce the nitrate content of vegetables to a degree necessary for optimum yield. The main aim during the cultivation period is therefore to control the N supply in such a way that too high applications are avoided and no excessive nitrate residues remain in the soil. Demands to go below that level are not justified according to recent knowledge and would lead to a distinctly higher cost of production.

Changing to ammonium can be recommended in many cases. This measure is, however, only effective if nitrification can be slowed down.

The grower can take additional steps by choosing cultivars which store little nitrate and cultivating in periods of high irradiation (e.g. spinach for industrial processing) and harvesting in the afternoon.

It is to be hoped that politicians will agree with the lower nitrate contents which can be obtained by the abovementioned measures of cultivation and fertilisation and will not make demands which affect cultivation drastically.

Prof. H C Scharpf, Lehr -u. Versuchsanstalt für Gartenbau, Hannover - Ahlen, Germany.

24 pages, 14 figures, 9 tables, 14 references.