Results showed that three treatments with the compound agent had effects on the decrease of nitrate content. Nitrate concentration of treatment with DCD reduced 24%, 20.1%, and 65.4% at three different stages respectively.

• 结果表明；加施复合剂的 3 个处理对生菜硝酸盐的降低效果较好；其中施用双氰胺的组合处理在 3 个生长时期的降低幅度分别为 24%25、20.；1%25、65