Understanding Yield Response to Nitrogen to Achieve High Yield and High Nitrogen Use Efficiency in Rainfed Corn

Abstract

Chinese farmers believe that more fertilizer and higher grain yields are synonymous. A better understanding of the relationship between corn ( Zea mays L.) yields and N rate could help agronomists match fertilizer rates with plant requirements. The objective of this study is to evaluate corn yield response to applied N fertilizer and to understand the factors affecting yield response to N fertilizer by 737 on‐farm experiments in northeastern China. Corn grain yield without applied N fertilizer averaged 7.6 Mg ha −1 . Increased yield for applied N fertilizer (IY N , the difference between maximum yield across all treatments and yield of the N 0 treatment) averaged 2.5 Mg ha −1 and varied from 0 to 9.3 Mg ha −1 . Farmers’ practices and corn hybrids resulted in large variability in IY N , whereas no changes in IY N occurred among years or soil types. Under the current cropping system, the maximum corn yield significantly increased and IY N decreased with increasing yield of the N 0 treatment, suggesting that increasing IY N with high yield of the N 0 treatment using integrated hybrids along with strategic management of crops, soils, and N is crucial for achieving high yields with a high N use efficiency (NUE).