Spectral Measurements of Alfalfa/Grass Fields Related to Forage Properties and Species Composition

ABSTRACT

The relationship between plant canopy reflectance and plant nutritive value has not been extensively investigated. The goal of this study was to relate spectral canopy reflectance to plant nutritive value and species composition. Multiple grass/alfalfa fields were analyzed using a field spectrometer, and then species composition, forage nutritive quality, and plant biomass were determined. Derivative analyses of spectra as well as narrow-band vegetation indices were used to examine the relationship between canopy reflectance and plant biophysical properties. Derivative analysis found a high correlation between high-order derivatives at multiple wavelengths and some plant properties, which include species composition and neutral detergent fiber (NDF). Wavelengths in the red region and between the red and near-infrared region of the spectrum showed the highest correlation in the derivative analysis. Analysis of whole canopy reflectance using spectroscopy may provide a quick, nondestructive method to determine plant characteristics.

Keywords:

• forage quality
• remote sensing
• spectroscopy