Remote sensing of chlorophyll level in corn at V6 growth stage based on spectral measurements has been limited by soil background, changes in cloud cover, and solar angles. Chlorophyll levels at V6 growth stage are a strong indicator of nitrogen status. This article suggests a solution based on an understanding of the hyperspectral characteristics of corn plants at different chlorophyll levels. Hyperspectral characteristics of corn plants with variable chlorophyll levels, under variable cloud cover, and with variable solar angles are presented. The chlorophyll levels were measured using the Minolta 502 chlorophyll meter. Investigation has found that spectral reflectance response patterns (SRRPs) of corn plants at the same chlorophyll level, acquired during cloud cover changes, still show consistent spectral pattern characteristics. The same characteristics were observed for SRRPs acquired as solar angles changed between 0950 and 1450 h. The results suggest that the SRRPs can be used to develop a robust model for predicting chlorophyll in corn at V6 growth stage. Furthermore, a strong correlation was obtained between chlorophyll readings (in SPAD units) and the near infrared/green (NIR/G) ratio (r2 = 0.94, root mean square error = 1.44 SPAD units) at constant solar irradiance.
|Original language||English (US)|
|Number of pages||9|
|Journal||Transactions of the American Society of Agricultural Engineers|
|State||Published - May 1 2002|
All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences (miscellaneous)