Effect of Nitrogen Nutrition and Planting Date on the Yield and Physicochemical Parameters of Flowering Chinese Cabbage

The nitrogen requirements of flowering Chinese cabbage are unknown. Our study aimed at investigating the effect of varied nitrogen nutrition levels (including 50, 70, 90, 110, and 130 mg N per dm3, described as N-50 to N-130, respectively) on the yield of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee) grown in two varied soilless cultivation systems (substrate and hydroponic) and seasons (spring and autumn). We confirmed that the intensity of the nitrogen nutrition modified the yield of plants within a range of 50 to 90 mg N; the yields were increased; however, the higher N concentrations were not effective. In both cultivation systems, the content of K, Ca, and Fe in leaves was higher in autumn compared to spring. Nitrogen nutrition improved the weight of plants—an effect that varied depending on the system of cultivation—and increased the phenolic content. N-90 was the optimal level of nitrogen nutrition. More intensive N-nutrition did not significantly modify plant yields or phenolic content. We Concluded that N fertilisation might be an effective tool to obtain plants with high bioactive compound content.