In order to derive recommendations for the nitrogen (N) fertilization of ca
rrots with high yield and low nitrate content, the effect of different leve
ls of nitrogen fertilization was tested for the cultivars Ingot (medium ear
ly harvest, fresh market) and Karotan (late harvest, processing). Data was
taken from field experiments carried out in 1992 and 1993 on a sandy soil w
here 0, 50, 100 and 150 kg N ha had been applied. In both cultivars, all fe
rtilizer treatments led to nitrate contents of carrot roots lower than the
German nitrate threshold value for baby food (250 mg NO3 kg(-1) on a fresh
weight basis). Treatments had no significant effect on either yield or nitr
ate content.
From the experimental data and from results found in the literature, it was
concluded that no nitrogen fertilizer should be applied for medium early c
arrot cultivars (total yield approximately 80 t ha(-1)) in sandy soils with
average nitrogen mineralization rates and that for late cultivars with hig
her yield (approximately 110 t ha(-1)) a soil mineral N target value of 75
kg N ha(-1) is appropriate.