Different Nitrogen Forms on the Growth and Nitrogen Utilization of Cucumber

Different nitrogen sources are effective on plants growth and yield. Ammonium [NH4-N], nitrate [NO3-N] and amide [CO (NH2)2] are the three different nitrogen sources. Here, we studied the effects of 9 ratios of different nitrogen forms with equal nitrogen on dry matter, nitrogen utilization and yield in cucumber. The results demonstrated that the yield of cucumber was enhanced as the proportion of nitrate increased in the ammonium and nitrate treatments except 100% nitrate. Nitrogen utilization efficiency in treatments with added amide were higher than in treatments with added ammonium with equal proportion of nitrate. A correlation analysis was performed; the proportion of nitrate and ammonium was significantly positively related to total dry matter, total nitrogen content and nitrogen utilization efficiency respectively (r = 0.919, 0.930, and 0.961), and nitrate-amide ratio was related to root-shoot ratio (r = 0.934). Additionally, there was a remarkably positive relationship between leaf nitrogen content and yield. Dry matter distribution, yield and root cap index may be regulated by the ratios of nitrogen forms. Moreover, cucumber yield is inseparable from its leaf nitrogen content. In conclusion, the nitrogen consisting of 75% nitrate+25% amide was superior to other treatments in cucumber growth in the present study.