Research on nitrogen content of leaf of Jincheng orange cultivar using visible near infrared spectroscopy model
YI Shi-lai,DENG Lie,HE Shao-lan,ZHENG Yong-qiang,ZHANG Xuan (Citrus Research Institute,Southwest University,Citrus Research Institute,CAAS,National Engineering Technology Research Center for Citrus,Chongqing 400712 China)
Visible/near-infrared spectroscopy (Vis/NIRS) appears as a prominent technique for non-destructive evaluation. In this research,the potential of using the Vis/NIRS was investigated for measuring the nitrogen content in Peng'an 100 Jincheng orange leaves,and the relationship was established between non-destructive VNIRS measurement and the nitrogen content in Peng'an 100 Jincheng orange leaves. Intact Peng'an 100 Jincheng orange leaves were measured by reflectance VNIR in 350 to 1000 nm range. The data set as the reflectance VNIR was analyzed in order to build the best prediction model for these characteristic,using several spectral pretreatments such as First Derivatives Spectrum (FDS),Second Derivatives Spectrum (SDS) and Reciprocal Logarithm Spectrum [Log (1/R)] with Standardization of Variables (SNV) techniques. The results showed the reflectance spectrums of leaves presented downward trend within 350 to 700 nm and upward trend within 750 to 1000 nm with the increasing of the nitrogen fertilizer in potted plant of Peng'an 100 Jincheng orange (Citrus sinensis Osbeck.) on trifoliate (Poncirous trifoliata) rootstock. The model for the nitrogen content in Peng'an 100 Jincheng orange leaves prediction using FDS with SNV spectral pretreatments showed an excellent prediction performance. This non-destruc-tive,fast and accurate technology can be used in citrus industry that would be beneficial to predict the plant nutrition.