Non-destructive monitoring of crop nitrogen nutrition based on spectral information
基于光谱信息的作物氮素营养无损监测技术

Nitrogen is one of the necessary nutrient elements for crop growth and yield formation,and the non-destructive,rapid and accurate monitoring of crop nitrogen nutrition is of significance in estimating crop growth parameters,enhancing nitrogen management and use efficiency,reducing farmland contamination from excessive use of fertilizer nitrogen,and promoting the research and application of precision farming and digital agriculture.In this paper,the mechanisms of non-destructive monitoring of crop nitrogen nutrition were interpreted with spectral and eco-physiological bases through clarifying the theoretical basis of the generation of crop nitrogen-specific spectra,responses of reflectance spectra to nitrogen nutrition,and physiological signification of spectral index.The research progress on the acquisition of reflectance spectra and the spectral-based monitoring of nitrogen nutrition in leaf,canopy and spatial levels were reviewed comprehensively,with the possible research directions recommended to address the urgent issues facing crop nitrogen monitoring and management in modern crop production,which included monitoring methods of nitrogen components,wide applicability of nitrogen estimation model,development of nitrogen monitoring apparatus,coupling of air-borne and ground-based spectral information,and integration of remote sensing and other key techniques.