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ARS Home » Research » Publications at this Location » Publication #78117
Title: SOIL COLOR, ORGANIC CARBON, AND HYDROMORPHOLOGY RELATIONSHIPS IN SANDY EPIPEDONS

Author
item LINDBO, D - N CAROLINA STATE UNIV
item RABENHORST, M - UNIV OF MARYLAND
item Rhoton, Fred

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Soil color is a primary property used to assess soil wetness for purposes of delineating hydric soil boundaries, especially for soils with sandy surface horizons. However, the standard Munsell soil color book is often inadequate because of its inability to separate subtle differences in color between samples. Our use of quantitative soil color determined with a chroma meter resulted in a much improved relationship between soil color and organic matter content, the primary coloring agent in these soils which also varies with soil wetness. Thus, the use of quantitative soil color has great potential in terms of improving the accuracy of the delineation of soil wetness boundaries

Technical Abstract: Quantitative assessment of soil color may increase the sensitivity of color determination to allow for the correlation of soil color to hydrology. One hydric soil indicator for sandy soils is dark colors (value/chroma <3/1) coupled with a high percentage (>70%) of organic coated sand grains in the surface mineral horizon. Observations indicate that as the percentage of uncoated sand grains increases soil color often lightens. Soil color therefore may serve as an additional indicator of wetness conditions; however, the Munsell soil color book lack sufficient detail to make specific determinations. Samples of A horizons were collected from a transect of sandy soil formed in late Pleistocene dunal deposits on the Delmarva Peninsula of Maryland. The soils represented were Quartzipsamments, Endoaquods, and Alaquods. Quantitative soil color was measured with a chroma meter using 5 absolute chromaticity systems (3 tristimulus systems, Yxy, L*a*b*, and L*C*H**0; Munsell system, hue, value, and chroma; and colorimetric density, Dxyz). The samples were measured air-dry and wet (saturated). Differential color was determined using the topographically lowest sample as the target sample to which all other samples were compared. Organic carbon was correlated to the observed color trends with a maximum r**2 of 0.63. In general, colorimetric density and hue of the Munsell system were not useful in relating color to either organic carbon or cumulative percent saturation.