China’s nitrogen management of wheat production needs more than high nitrogen use efficiency

• Published in: European journal of agronomy 2022-09, Vol.139, p.126557, Article 126557
• Main Authors: Bai, Nan, Mi, Xiaotian, Tao, Zhenkui, Kang, Jiayi, He, Gang, Wang, Zhaohui
• Format: Article
• Language: English
• Subjects: 15N-labelled method; Farmers survey; N management techniques; N surplus; N-difference method
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/j.eja.2022.126557

Nitrogen (N) fertilizer is essential for increasing yields in intensive agricultural systems, but it also creates an environmental burden. Improving recovery efficiency of N (REN) is the key to balancing the trade-off between crop production and environmental protection. However, the current status of the REN in China and whether a high REN is sufficient for sustainable wheat production remain unclear. Here we estimated the REN of wheat production in China using N-difference method and 15N-labelled method, explored strategies to improve REN, and clarified that China’s nitrogen management of wheat production needs more than high nitrogen use efficiency. The findings of a 12-year field trial showed that the REN estimated by N-difference method was double that estimated by 15N-labelled method, and meta-analysis results showed that the national mean REN estimated by the two methods were similar, ranging from 30% to 33%. Notably, the REN was consistently lower than the global mean according to both methods; thus, exploring strategies to improve REN is vital. Results showed that reducing N fertilizer application rate and N surplus are essential for improving REN; however, indiscriminately reducing N application rate creates a great risk of reducing yields since insufficient and excessive use of N fertilizer is prevalent in wheat production of many counties. The establishment of the inherent interconnections among REN, crop yield, and N surplus showed that REN or N surplus should be used together with yield as an indicator of the sustainability of crop systems. The implementation of comprehensive N management techniques increased REN (38–104%) and yield (8–9%) while reducing N surplus (52–89%), which provides a good starting point for further discussions of N fertilizer management for sustainable wheat production. •National average REN of N-difference method and 15N-labelled method is 30–33%.•Blindly reducing N rate may reduce wheat yield due to larger variations among counties.•REN or N surplus should be used together with crop yield as an indicator of crop systems.•Comprehensive N management provides good opportunity for sustainable wheat production.