Abstract:

【Objective】 Red edge position (REP, 680-780 nm) has been used for evaluating crop leaves nitrogen status. The objectives of this paper were to extract REP with different algorithms, to analyze the precision and stability of the monitoring model, to ascertain the optimum REP algorithm and relevant quantitative model for nitrogen status. 【Method】 On the basis of hyperspectral reflectance and leaf nitrogen status at different growth stages under varied nitrogen rates, planting densities and wheat cultivars, this study systematically analyzed the quantitative relationships and statistical characters between red edge position on various algorithms and canopy leaf nitrogen status, and then developed the monitoring models by comparing accuracy and reliability of nitrogen estimation. 【Result】 The results showed that the monitoring models developed from the linear extrapolation method (LEM) could stably indicate canopy leaf nitrogen content (LNC) and leaf nitrogen accumulation (LNA) in wheat. 【Conclusion】 The results have provided a stable and effective approach for monitoring canopy leaf nitrogen status in wheat.

Key words: different algorithm')">different algorithm, red edge position, monitoring, winter wheat, canopy, nitrogen status