Nitrogen Time of Application Impact on Productivity, Water Use Efficiency and Agronomic Efficiency of Maize in a Semi-arid Environment

Water is one of the most important limiting factor of rainfed continuous maize (Zea mays L.) cropping systems in northwest of China. A three continuous year field experiments were conducted to study the influence of different nitrogen time of application on grain yield and water use efficiency of maize (Zea mays L.) in the Western Loess plateau. The experiment was laid in a randomized complete block design with two treatments and three replicates. Treatments were; (one-third application of N at sowing + two-third application at pre-flowering) and (one-third application of N at sowing + one-third pre-flowering + one-third at milking) as T1 and T2 respectively. The results showed that, T1 significantly increased grain yield by 9% in 2014 and 2016; and WUE by 11% in 2016 compared to T2. T1 increased AE by 43% compared to T2. Our results indicate that ⅓ application of Nitrogen at sowing and ⅔ application of Nitrogen at pre–flowering (T1) for maize is more appropriate for sustainable maize production in terms of satisfactory grain-N recoveries and low environmental losses of N fertilizer.