| Cite this article: | 马岩川,刘浩,陈智芳,等.不同水分条件下棉花冠层含氮量高光谱监测研究[J].灌溉排水学报,0,():-. |
| Ma Yanchuan,Liu Hao,Chen Zhifang,et al.不同水分条件下棉花冠层含氮量高光谱监测研究[J].灌溉排水学报,0,():-. |
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| Study on hyperspectral monitoring of canopy nitrogen content in cotton under different water conditions |
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Ma Yanchuan, Liu Hao, Chen Zhifang, Zhang Kai, Wang Jinglei, Sun Jingsheng
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Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences
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| Abstract: |
| Abstract: 【objective】To establish a CNC monitoring model of cotton whitch suitable for different water conditions.【Method】Irrigation gradient and nitrogen application gradient were set up in the field.Information such as spectral reflectance, canopy nitrogen content (CNC) and Canopy equivalent water thickness (CEWT) were measured simultaneously during the growth period. The correlation between nitrogen content and equivalent water thickness of cotton canopy and spectral index was analyzed comprehensively, and the optimal spectral index was determined and the hyperspectral monitoring model of cotton CNC was constructed.【Results】Canopy spectra and CNC have continuous sensitive regions near visible and near-infrared bands，and the maximum correlation coefficient |r| Max is 0.53, located at 718nm. NDSI (800,770) had the best modeling effect (R2 = 0.76) when the influence of CEWT on the model accuracy was not considered. However, in the late stage of flower boll, the prediction accuracy was low and the phenomenon of underestimation appeared. After comprehensively considering the influence of CEWT, NDSI(570,500) was selected as the optimal spectral index in this study，and the model can effectively improve the low accuracy of the model caused by water content (RRMSE=0.18). 【Conclusion】NDSI(570,500), a new moisture insensitive spectral index established in this study, can effectively improve the estimation accuracy of cotton CNC. It provides the technical basis for the application of hyperspectral technology in monitoring nitrogen fertilizer in cotton field. |
| Key words: Hyperspectral; Cotton; Different Water Gradients; Canopy Nitrogen Content |
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