Understanding and reconciling different approaches for quantifying nitrogen use efficiency in cropping systems [post]

Zhi Quan, Xin Zhang, Yunting Fang, Eric Davidson
2020 unpublished
Nitrogen use efficiency (NUE) has been widely used in cropping systems to study nitrogen (N) cycles and inform N management on various spatial scales, from a single plant to the globe. Although the number of NUE studies is growing, interpretation of results is unfortunately hindered by widely differing definitions and quantification methods among studies, suggesting a pressing need for harmonization of approaches. Here, we proposed a conceptual framework to understanding the differences and
more » ... differences and connections among three major approaches for determining NUE, namely, the difference approach, 15N tracer approach, and N balance approach. Using the Chinese cereal cropping system as an example, we demonstrated that the results of those NUE assessments could be very different even for the same cropping system (0.32, 0.24, and 0.52, respectively). Such a difference is attributable largely to the soil legacy effect and could be reduced by extending the observations for a longer term. This study provides the necessary understanding to reconcile NUE values from different approaches and consequently to better inform N management in cropping systems.
doi:10.21203/rs.3.rs-60369/v1 fatcat:ifwtwrinivczpdodwgiotvrlbq