Pedosphere 8(2): 121--126, 1998
ISSN 1002-0160/CN 32-1315/P
©1998 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Feasibility of field evaluation of rice nitrogen status from reflectance spectra of canopy |
| WANG Ren-Chao, WANG Ke and SHEN Zhang-Quan |
| Institute of Agricultural Remote Sensing and Information Application, Zhejiang Agricultural University, Hangzhou 310029 (China) |
| ABSTRACT |
| Techniques for measurement of the N status of rice can be an aid to making management decisions with economic and environm entalimplications. A field experiment was conducted to identify spectral variables most sensitive to N deficiency detection in rice canopy with the possibility for their use as a management tool. Spectral and agronomic measurements were collected in the evaluation experiment of N status from rice canopy under five N treatments in a silt loam soil. Nitrogen fertilization effects were seen across the entire wavelength measured. Red reflectance decreased and near infrared reflectance increased with increasing N fertilizer application. Spectral differences between treatments were seen throughout the test period. The near infrared reflectance/red reflectance ratio (RVI) differed more betw een treatments than between single bands. Variations in canopy reflectances due to other environmental factors were reduced by the use of RVI. In the spectral variables examined, the RVI separated the treatments most effectively, and three or four treatments can be separated. Differences in spectral responses between the treatments were attributable to leaf area index, leaf chlorophyll concentration and phytomass, which all changed with N fertilization. |
| Key Words: canopy spectra, nitrogen fertilizer, nitrogen status evaluation, rice |
| Citation: Wang, R. C., Wang, K. and Shen, Z. Q. 1998. Feasibility of field evaluation of rice nitrogen status from reflectance spectra of canopy. Pedosphere. 8(2): 121-126. |
| |
|
View Full Text
|
|
|
|
