Response of different varieties of maize to nitrogen stress and diagnosis of leaf nitrogen using hyperspectral data

Spectral technology is theoretically effective in diagnosing N stress in maize (Zea mays L.), but its application is affected by varietal differences. In this study, the responses to N stress, leaf N spectral diagnostic models and the differences between two maize varieties were analysed. The variety Jiyu 5817 exhibited a greater response to different N stresses at the 12-leaf stage (V12), while Zhengdan 958 displayed a greater response in the silking stage (R1). Correlation analysis showed that the spectral bands more sensitive to leaf N content were 548-556 nm and 706-721 nm at the V12 stage in Jiyu 5817 and 760-1142 nm at the R1 stage in Zhengdan 958. An N spectral diagnostic model that considers the varietal effect improves the model fit and root mean square error (RMSE) with respect to the model without it by 10.6% and 29.2%, respectively. It was concluded that the V12 stage for Jiyu 5817 and the R1 stage for Zhengdan 958 were the best diagnostic stages and were more sensitive to N stress, which can further guide fertilization decision-making in precision fertilization.

Automated summary

Spectral technology is effective in diagnosing N stress in maize, but it is affected by varietal differences. The responses to N stress, leaf N spectral diagnostic models, and varietal differences were analyzed in this study. The diagnostic stages for Jiyu 5817 and Zhengdan 958 were identified, and considering varietal effect in the diagnostic model improved its fit and RMSE.