Various Types of Nitrogen and Light Levels on Brassica chinensis Yield and Quality Parameters under Water Stress

To evaluate the effect of nitrogen, light, and water interaction on the biomass of cabbage the experiment was performed at three light intensities, three water stresses, and four nitrogen levels for four replicates using hydroponic technique in green house. The results showed that the biomass of the edible parts of cabbage at H1L3 was significantly higher than in weak light intensity and water stress treatments under the same nitrogen supply. An optimal yield was reached at 60% of the traditional nitrogen application in the presence of adequate high light intensity and normal water content. Decreased nitrate reductase and low capacity of nitrogen assimilation were observed when the nitrate-nitrogen (NO3-N) levels were increased from N2 to N4 with normal water content. Under severe water stress (H3), the plants have a high content of soluble sugars and a low content of amino acids in low NO3- levels (N1 to N3). Modulating the relationship between water stresses, light intensity, and nitrogen supply levels could increase the biomass and may promote the quality of a certain plant.