B. Mistele and U. Schmidhalter, Estimating the nitrogen nutrition index using spectral canopy reflectance measurements, European Journal of Agronomy, vol.29, issue.4, pp.184-190, 2008.
DOI : 10.1016/j.eja.2008.05.007

G. Jianhua, Z. Chunjiang, and W. Xiu, Research advancement and status on crop nitrogen nutrition diagnosis[J]. Soils and Fertilizers Sciences in China, pp.10-14, 2008.

L. Minzan, H. Donghai, and W. Xiu, Spectral Analyzing technique and Applications, pp.177-194, 2006.

I. Filella, L. Serrano, and J. Serra, Evaluating Wheat Nitrogen Status with Canopy Reflectance Indices and Discriminant Analysis, Crop Science, vol.35, issue.5, pp.35-1400, 1995.
DOI : 10.2135/cropsci1995.0011183X003500050023x

X. Lihong, C. Weixing, and L. Weihong, Monitoring leaf nitrogen status in rice with canopy spectral reflectance, Agronomy Journal, vol.96, issue.1, pp.135-142, 2004.

M. L. Stone, D. Needham, and J. B. Solie, Optical spectral reflectance sensor and controller: U.S. Patent 6, p.996, 2003.

N. Jun, Y. Xia, and T. Yongchao, Design and experiments of portable apparatus for plant growth monitoring and diagnosis. Transactions of the Chinese Society of Agricultural Engineering, pp.150-156, 2013.

L. Zhang-xijie, C. Minzan, and . Di, New method and instrument to diagnose crop growth status in greenhouse based on spectroscopy, Spectroscopy and Spectral Analysis, vol.26, issue.5, pp.887-890, 2006.

L. Xiuhua, L. Minzan, and C. Di, Non-destructive crop canopy analyzer based on spectral principle. Transactions of the Chinese Society for Agriculture Machinery, pp.40-252, 2009.

L. Xiuhua, Z. Feng, and L. Minzan, Design of a Four-waveband Crop Canopy Analyzer. Transactions of the Chinese Society for Agricultural Machinery, pp.42-169, 2012.

R. Sui, J. Wilkerson, W. Hart, L. Wilhelm, and D. Howard, Multi?spectral sensor for detection of nitrogen status in cotton Applied engineering in agriculture, pp.167-172, 2005.

Y. Shuping, A measuring technology for normalized difference vegetation index, Journal of Basic Science and Engineering, vol.12, issue.3, pp.328-332, 2004.