Real-time nitrogen management for spring maize using the soil nitrate-N test

With a three-year field experiment, the real-time nitrogen (N) management for spring maize was constructed to synergistically increase crop yield and fertilizer N efficiency based on the soil nitrate-N test. The results show that the optimal recommended N application rate is significantly lower than that of the traditional practice, and the amount of saving N fertilizer is about 60 kg/ha per year. Compared with the traditional practice, the grain yield under the optimal N rate is increased by 6.43% due to synchronizing N supply from soil and fertilizer, and N demand of spring maize. In addition, N use efficiency, N agronomic efficiency, N physiological use efficiency and N partial productivity are significantly improved. Therefore, it is preliminarily concluded that the real-time N management constructed in this study is reasonable, and the application of real-time N management to spring maize can realize synchronization of N application rate decrease, grain yield increase, N efficiency improvement and environment protection.