Field conditions and the accuracy of visually determined Munsell soil color

Abstract

AbstractThis study evaluated the effect of variable natural lighting on the accuracy of soil color determination using the Munsell color charts. The effect of clouds, shade, and time of day were measured by calculating the distance between colors determined with the Munsell charts and colors measured with a chromameter. The only condition found to negatively affect accuracy was early‐morning light on sunny days, and this effect was only significant for individuals with high overall accuracy at reading soil color. Regressions of visual color relative to chromameter color showed a reduction in slope and R2 value for chromas measured early in the morning (m = 0.56, R2 = 0.75) compared with mid‐day (m = 0.67, R2 = 0.93) on sunny days. Overall, these results suggest that variation in natural lighting does not have a large impact on visual color determination; however, sunny mornings should be avoided when accuracy is critical.