Landsat Individual Band Correlation to Soybean Yield
Using NIR reflectance, solely, from R2 to R6 for soybean yield prediction assures that the canopy is closed enough to diminish the soil background influence enough. The R2 to R6 stages include most of the dates in the plots; the range excludes the growth stage associated with the negative NIR correlation in the latest image date as well as some others, but includes most.
Symbology: blue = Landsat band 1 (blue band); green = Landsat band 2 (green band); red = Landsat band 3 (red band); dark red = band 4 (NIR band)
Landsat Blue, Green, Red, and NIR band Correlation (r) to Soybean Yield (Hollinger, 2011)
Linear correlations (r) between Landsat pixel reflectance and clean soybean yield monitor data for fields in northwest Ohio during different times/growth stages of the season from Hollinger (2011). Correlations are between reflectance and the average of clean yield monitor data within the extent of the pixel; fields are different sizes but this is not statistically important to correlation level. Seasons had fairly typical planting dates. Above symbology is as follows: blue is Landsat band 1 (blue band), green is Landsat band 2 (green band), red is Landsat band 3 (red band), and dark red is band 4 (NIR band). Numbers correspond to images dates based on growing degree days; the darker the blue the more precipitation in the previous three days immediately prior to the image date. Image date 6 is the time when the canopy, as a rule of thumb, is overall closed enough whereby the soil influence is diminished enough for yield correlation purposes.
Reference
Hollinger, D. 2011. Crop Condition and yield prediction at the field scale with geospatial and artificial neural network applications. Dissertation. Kent State University.