Andrzej Kalisz

This study was carried out in the years 2003-2005 on the effect of different nitrogen fertilization on the yield and chemical composition of field-grown Chinese cabbage produced for autumn harvests. All experimental plots were initially fertilized with 100 kg N·ha^-1 before transplanting. Additionally, the following doses of nitrogen were applied during vegetation period: 20, 60, and 100 kg N·ha^-1. The lowest total yield was obtained at the lowest tested nitrogen dose of 20 kg N·ha^-1. The results demonstrated that increasing nitrogen rates increased the marketable yield on average by 5.16 t·ha^-1 (60 kg N·ha^-1) and 5.49 t·ha^-1 (100 kg N·ha^-1) in comparison to 20 kg N·ha^-1. However, the number of Chinese cabbage plants suitable for trading and the average weight of marketable heads were statistically similar. The highest content of dry weight and L-ascorbic acid was noted in Chinese cabbage fertilized with 60 kg N·ha^-1 (4.45% f.w. and 20.27 mg·100 g^-1 f.w., respectively). It was also observed that the nitrogen dose of 100 kg N·ha^-1 caused the highest accumulation of thiocyanates (23.76 μg KSCN·g^-1 f.w.). The nitrates and total N accumulation in Chinese cabbage continuously increased with N rate - from 1454.7 mg NO₃·kg^-1 f.w. and 2.93% d.w. (20 kg N·ha^-1) to 1784.5 mg NO₃·kg^-1 f.w. and 3.22% d.w. (100 kg N·ha^-1). The soluble sugar and crude fiber content was not significantly influenced by nitrogen fertilization.