Poster, Art, Science and Applications of Reflectance Spectroscopy Symposium, Boulder (CO, USA): 23.02.2010 - 25.02.2010
Brilliant Blue is often used to trace water movement in soils. Its concentration in soil samples is usually determined by extraction – a laborious procedure with varying accuracy. We show that Brilliant Blue can be measured directly by visible diffuse reflectance spectroscopy. We build a PLSR (partial least squares regression) model for the concentration range of 0.1 to 15 mg Brilliant Blue per g soil with an RMSE (root mean square error of prediction) of 1 mg g-1 and an R2adj of 0.9. As the method is based on visible spectra, prediction accuracy can be seriously affected by variation in soil colour between calibration and prediction data sets.