Pedosphere 16(3): 333--338, 2006
ISSN 1002-0160/CN 32-1315/P
©2006 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Relationship of 2100-2300 nm spectral characteristics of wheat canopy to leaf area index and leaf n as affected by leaf water content |
ZHAO Chun-Jiang1 , WANG Ji-Hua1, LIU Liang-Yun1, HUANG Wen-Jiang1 and ZHOU Qi-Fa12 |
1 National Engineering Research Center for Information Technology in Agriculture, Beijing 100089 (China). E-mail: zhaocj@nercita.org.cn
2 The State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310012 (China) |
| ABSTRACT |
| The effects of leaf water status in a wheat canopy on the accuracy of estimating leaf area index (LAI) and N were determined in this study using extracted spectral characteristics in the 2 000-2 300 nm region of the short wave infrared (SWI) band. A newly defined spectral index, relative adsorptive index in the 2000-2300 nm region (RAI2000-2300), which can be calculated by RAI2000-2300 = (R2224 - R2054) (R2224 + R2054)-1 with R being the reflectance at 2224 or 2054 nm, was utilized. This spectral index, RAI2000-2300, was significantly correlated (P < 0.01) with green LAI and leaf N concentration and proved to be potentially valuable for monitoring plant green LAI and leaf N at the field canopy scale. Moreover, plant LAI could be monitored more easily and more successfully than plant leaf N. The study also showed that leaf water had a strong masking effect on the 2 000-2 300 nm spectral characteristics and both the coefficient between RAI2000-2300 and green LAI and that between RAI2000-2300 and leaf N content decreased as leaf water content increased. |
| Key Words: leaf area index, nitrogen, plant water status, reflectance, Triticum aestivum L. |
| Citation: Zhao, C. J., Wang, J. H., Liu, L. Y., Huang, W. J. and Zhou, Q. F. 2006. Relationship of 2100-2300 nm spectral characteristics of wheat canopy to leaf area index and leaf n as affected by leaf water content. Pedosphere. 16(3): 333-338. |
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