Figure 5. Quadratic-plateau functions describing the relationship between alfalfa yield and wide dynamic range vegetation indices (WDRVIs) calculated using one of three near-infrared (NIR) reflectance-scalars (‘’ = 0.1, 0.05, and 0.01). Canopy reflectance measurements from which the indices are calculated were made 1 d before each of the five harvests during 2005 using the FieldScan. Observations for a given harvest consist of the mean VI and total plot yield measured from each plot (n = 80).