Different quantification approaches for nitrogen use efficiency lead to divergent estimates with varying advantages

Nitrogen use efficiency (NUE) is a key indicator with which to study nitrogen cycles and inform nitrogen management. However, different quantification approaches may result in substantially divergent NUE values even for the same production system or for the same experimental plot. Based on our investigation of the differences between and connections among the three principal approaches for NUE quantification, we offer recommendations for choosing the appropriate approach and call for long-term observations to assess the impacts of management practices. Different methods are currently used to quantify nitrogen use efficiency. The comparison of three such methods based on real-world experiments shows the impact of indicator choice on results, while highlighting the importance of long-term observations.