X. B. Zeng and J. M. Li, Fertilizer Application and its Effect on Grain Production in Different Counties of China (in Chinese), Scientia Agricultura Sinica, vol.37, pp.387-392, 2004.

W. J. Jiao, Q. W. Min, K. Lin, Q. K. Zhu, and J. J. Zhang, Progress and Perspective on Nutrition Diagnosis of Plant Nitrogen (in Chinese), Chinese Agricultural Science Bulletin, vol.22, pp.351-355, 2006.

Y. C. Tian, Y. Zhu, X. Yao, X. J. Liu, and W. X. Cao, Non-destructive Monitoring of Crop Nitrogen Nutrition Based on Spectral Information (in Chinese), Chinese Journal of Ecology, vol.26, pp.1454-1463, 2007.

J. R. Thomas and G. F. Oerther, Estimating Nitrogen Content of Sweet Pepper Leaves by Reflectance Measurements1, Agronomy Journal, vol.64, issue.1, pp.11-13, 1972.
DOI : 10.2134/agronj1972.00021962006400010004x

L. Filella, L. Serra, and J. Penuelas, Evaluating Wheat Nitrogen Status with Canopy Reflectance Indices and Discriminant Analysis, Crop Science, vol.35, issue.5, pp.1400-1405, 1995.
DOI : 10.2135/cropsci1995.0011183X003500050023x

M. Shibayama and T. Akiyama, A spectroradiometer for field use. VII Radiometric estimation of nitrogen levels in field rice canopies., Japanese journal of crop science, vol.55, issue.4, pp.433-438, 1986.
DOI : 10.1626/jcs.55.439

S. Watanabe and T. Kuzunuki, Method of and Device for Measuring Chlorophyll of Living Leaves, Japan, 1981.

F. T. Turner and M. F. Jund, Chlorophyll Meter to Predict Nitrogen Topdress Requirement for Semidwarf Rice, Agronomy Journal, vol.83, issue.5, pp.926-928, 1991.
DOI : 10.2134/agronj1991.00021962008300050029x

L. H. Wu and Q. N. Tao, Nitrogen Fertilizer Application Based on the Diagnosis of Nitrogen Nutrition of Rice Plants (Oryza sativa L.) Using Chlorophyll Meter (in Chinese), Journal of Zhejiang Agricultural University, vol.25, pp.135-138, 1999.

W. P. Piekielek and R. H. Fox, Use of a Chlorophyll Meter to Predict Sidedress Nitrogen, Agronomy Journal, vol.84, issue.1, pp.59-65, 1992.
DOI : 10.2134/agronj1992.00021962008400010013x

R. H. Follett and R. F. Follett, Use of a chlorophyll meter to evaluate the nitrogen status of dryland winter wheat, Communications in Soil Science and Plant Analysis, vol.4, issue.7-8, pp.687-697, 1992.
DOI : 10.2134/agronj1990.00021962008200030025x

M. M. Shaahan, A. A. Ei-sayed, and E. A. Abou-ei-nour, Predicting nitrogen, magnesium and iron nutritional status in some perennial crops using a portable chlorophyll meter, Scientia Horticulturae, vol.82, issue.3-4, pp.339-348, 1999.
DOI : 10.1016/S0304-4238(99)00060-6

S. X. Chang and D. J. Robison, Nondestructive and rapid estimation of hardwood foliar nitrogen status using the SPAD-502 chlorophyll meter, Forest Ecology and Management, vol.181, issue.3, pp.331-338, 2003.
DOI : 10.1016/S0378-1127(03)00004-5

H. Y. Li, Q. P. Ren, S. Sun, and H. Y. Ma, Study on Relation between SPAD Value and Chlorophyll Contents in 10 Kinds Horticulture Woody Plants (in Chinese), Forestry Science and Technology, vol.34, pp.68-70, 2009.

H. K. Lichtenthaler and A. R. Wellbuen, of leaf extracts in different solvents, Biochemical Society Transactions, vol.11, issue.5, pp.591-592, 1983.
DOI : 10.1042/bst0110591

J. S. Schepers, T. M. Blackmer, W. Wilhelm, and M. Resende, Transmittance and Reflectance Measurements of CornLeaves from Plants with Different Nitrogen and Water Supply, Journal of Plant Physiology, vol.148, issue.5, pp.523-529, 1996.
DOI : 10.1016/S0176-1617(96)80071-X

W. L. Bauerle, D. J. Weston, J. D. Bowdena, J. B. Dudley, and J. E. Toler, Leaf absorptance of photosynthetically active radiation in relation to chlorophyll meter estimates among woody plant species, Scientia Horticulturae, vol.101, issue.1-2, pp.169-178, 2004.
DOI : 10.1016/j.scienta.2003.09.010

L. H. Fuchigami, P. H. Ding, and G. E. Barnes, Portable Meter to Measure Chlorophyll, 2007.