Winter oilseed-rape yield estimates from hyperspectral radiometer measurements

Abstract

Spectral reflectance data can be used for estimation of plant biophysical parameters such as seed yield, related to the use of solar energy. A field experiment was conducted to investigate relationships between canopy reflectance and seed yield of winter oilseed rape sown on four different dates. Ground hyperspectral reflectance measurements were made using a hand-held radiometer and multispectral images were taken with a VIS-NIR camera. The different sowing dates generated a wide range of difference in crop spectral response and seed yields. The strongest relationships (R2=0.87) between the yield and spectral data recorded by both sensors occurred at early flowering stages. Later, the presence of flowers caused a decline in the relationship between yield and spectral data especially in the visible (VIS) range. In the full flowering stage the strongest correlation (R2=0.72) with the yield showed vegetation indices of the near-infrared (NIR) bands.