Analysis of soil color variables and their relationships between two field-based methods and its potential application for wetland soils

• Published in: The Science of the total environment 2021-08, Vol.783, p.147005-147005, Article 147005
• Main Authors: Schmidt, Stephanie A., Ahn, Changwoo
• Format: Article
• Language: English
• Subjects: Hydric soils; Munsell Soil Color Chart; Nix Color Sensor; Soil color; Wetland delineation; Wetland soil
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2021.147005

While the Munsell Soil Color Chart (MSCC) is the most frequently used, well-established field method for reading soil color, the Nix Color Sensor (NCS) is an inexpensive, app-based alternative that can complement or potentially substitute for the MSCC. Soils were collected and their colors were measured from four forested sites across Northern Virginia within the Chesapeake Bay Watershed using both the MSCC and NCS. Three MSCC variables and 15 NCS variables were collected in the field; a methodology was established to use these “measured” (M) variables to derive 9 NCS calculated (C) variables. A stepwise correlation identified NCS variables most suitable for relating the NCS to each of the MSCC attributes: hue (H), value (V), and chroma (CM). Ultimately, H, V, and CM were deemed to be best represented by HRGB calculated from the RGB color space (ρ = 0.56), L from the CIE-Lab color space (ρ = 0.73), and ẑ = Z/(X + Y + Z) from the XYZ color space (ρ = −0.80), respectively (p < 0.001). The corresponding explanatory powers of final NCS variables (i.e., HRGB, L, and ẑ) for H, V, and CM were 26%, 54%, and 62%, respectively (p