Effects of different nitrogen levels on the growth and quality of spinach

Hydroponical experiment was carried out to study the effects of different nitrogen levels (5,10,15,20 mmol·L~-1)on biomass,nitrate and soluble sugar contents in different parts in spinach(Spinacia oleracea).The optimal nitrogen level for spinach growth was 15 mmol·L~-1.The content of nitrate increased with the increasing of nitrogen levels,while soluble sugar decreased,which indicated that proper nitrogen management could improve the quality of spinach.