Advances in the estimations and applications of critical nitrogen dilution curve and nitrogen nutrition index of major cereal crops. A review.

• Remote sensing technologies has greater application potential in N diagnosis. • Dilution curves are helpful for an in-depth understanding of G × E × M interactions. • The newly developed Bayesian method has the potential to minimize uncertainties. Nitrogen (N) is one of the decisive elements for plant growth, crop biomass accumulation, and yield formation of cereal crops. However, managing N in crop production and comparing N use efficiency are challenging without prior knowledge of in-season crop N status. The development of critical N (N c) dilution curves based on allometry between plant metabolic and structural compartments allows the estimation of crop N nutrition status by determining the N nutrition index (NNI). The purpose of this article is to review the research progress on the development of N c curves in three major cereal crops (wheat, maize, and rice). The focus of this review paper is to compare the N c curves of major cereals developed worldwide and to explain the differences in these N c curve parameters in light of genotype through the management of environmental interactions. Additionally, this review provides an update on the most relevant methods for non-destructive estimation of the NNI of major cereal crops using various remote sensing technologies for large-scale applications. This review also sheds light on the applicability of N c curve-based NNI for in-season crop N diagnosis, crop N requirement, crop grain yield, and quality prediction. Moreover, this review outlines future research directions to expand the impact of this approach on crop production. [ABSTRACT FROM AUTHOR]