REDUCING NITROGEN LOSSES BY DECREASING MINERAL FERTILIZATION IN HORTICULTURAL CROPS OF EASTERN SPAIN

Three experiments were carried out using horticultural plants (articho ke. cabbage and potato) in southeast Spain (Alicante) for two cropping seasons, A reduced mineral fertilisation treatment (-N, less than 300 kg N ha(-1)) was compared with the traditional input of nitrogen (+ N , around 500 kg N ha(-1)) to evaluate the losses of mineral forms in t he soil profile, quantity of plant nitrogen and yield. Three plots wer e used, Nitrate, ammonium and organic N were measured in the soil prof ile at four depths (0-30, 30-60, 60-90 and 90-120 cm), and amounts of plant nitrogen in the aerial and edible parts of the plant evaluated, together with the marketable yields in each season. Nitrogen losses we re reduced, especially in the second season, but plant nitrogen and yi eld were not significantly affected.