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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Publications at this Location » Publication #314128
Title: Spectral indices for yellow canola flowers

Author
item Sulik, John
item Long, Daniel

Submitted to: International Journal of Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2015
Publication Date: 5/20/2015
Publication URL: http://handle.nal.usda.gov/10113/1357868
Citation: Sulik, J.J., Long, D.S. 2015. Spectral indices for yellow canola flowers. International Journal of Remote Sensing. 36:2751-2765.

Interpretive Summary: Flowers interfere with ability to use light that is reflected from green leaves to determine the condition of growing plants. This study was conducted to determine how flowers influence reflectance of light from plants and what bands of light are useful for estimating flower number and plant biomass. The effects of flower number and biomass on the amount of blue, green, red, and near infrared light reflected from spring canola were investigated in a field study consisting of three water regimes and three fertilizer nitrogen levels near Pendleton, OR, USA. The result of dividing blue light by green light was strongly related to the number of yellow flowers per unit area. Dividing near-infrared light by blue light was most suitable for estimating biomass during flowering. Information on the quality and quantify of light reflected from plants during flowering may improve how remote sensing is used to describe plant development and reproductive capacity during the growing season.

Technical Abstract: Reproductive growth, such as flowers, may contribute to a canopy-level signal yet there are not currently any indices that measure variation in flowering. This study was conducted to determine how flowers influence the overall canopy signal and what bands of light may be useful for estimating variation in flower density and LAI. The effects of flower number and LAI on canopy spectral reflectance of spring canola (Brassica napus L.) were investigated in a field study consisting of three water regimes and three fertilizer N levels near Pendleton, OR, USA. A band ratio of green and blue light was strongly (r2 = 0.87) related to the number of yellow flowers per unit area whereas a ratio of near-infrared and blue light was most suitable for estimating LAI during flowering. Spectral information during flowering may improve how remote sensing is used to describe plant development and reproductive capacity during the growing season.