The Effect of Nitrogen Rates on Yields and Nitrogen Use Efficiencies during Four Years of Wheat–Maize Rotation Cropping Seasons

Abstract

Nitrogen is a major limiting factor to crop production of the intensive wheat (Triticum aestivum L.)–maize (Zea mays L.) rotation cropping system in the North China Plain (NCP). This 4‐yr study was to evaluate the effects of N application on soil NO3–N dynamics and N use efficiency under sprinkler irrigation in the Beijing region of the NCP. There were four treatments, named CK, N1, N2, N3 with N application of 0, 110, 220, and 330 kg N ha−1 per crop season, respectively. Results indicate that no water and NO3–N leached out of the 0 to 100 cm soil layer in the winter wheat seasons, whereas they moved into soil layers deeper than 100 cm in the summer maize seasons. After the 4‐yr cropping, the NO3–N concentration in the 0 to 120 cm soil profile decreased for CK, then remained relatively stable for N1 treatment, and increased greatly for N2 and N3 treatments. Generally, N application improved crop growth and increased N efficiencies and water use efficiency. Mostly, growth parameters and yields were not significantly (P > 0.05) different among the N1‐to‐N3 treatments, while N efficiencies decreased with N application increasing. Considering the economic benefit and environmental risk, N application rate of 110 to 130 kg N ha−1 per crop season is recommended for the wheat–maize rotation cropping system under sprinkler irrigation in the Beijing area and those regions with similar climatic conditions and soil properties in the NCP. Larger deep percolation and nitrate leaching were found in maize season than those in wheat season. Nitrogen application greatly improved crop growth and yield. Application of 110 to 130 kg N ha−1 per crop season is recommended for the wheat–maize cropping system in the North China Plain.