Use of color splitting and a computer technique to separate soil moisture groups
1989
Al-Abed, S.R. | Lewis, D.T. | Samson, S.A.
A method to quantify the distribution of colors across the surface and interior of soil peds was developed and used on soils that differed in morphological indicators of soil drainage. Soils from two contrasting geomorphic settings were selected for study. In the first of these settings, morphological indicators have not appeared to be useful predictors of actual soil wetness. In the second setting, soil morphology appears to predict wetness reasonably well. Pedons in the second setting provided an independent set of data against which to evaluate judgments made about pedon wetness of the first geomorphic setting. Pedon morphology was determined and duration of saturation was measured for all pedons studied. Saturation measurements were used to place pedons studied in a wet, medium, or dry moisture group. Ped surfaces and interiors were photographed using a 35-mm camera and color slides were prepared. Color patterns on these slides were analyzed using a digital densitometer. Colors (red, green, and blue) were separated through use of the corresponding filters. Densities of these colors on each slide were determined and ranked within six brightness subranges. Cluster analysis was used to group the color rankings. Groups formed through this procedure coincided with groups (wet, medium, or dry) formed through measurement of duration of saturation. This procedure appeared to be better able to predict actual saturation than did commonly used methods based on horizon color and/or mottle features. It appears to provide a method to remove subjectiveness from soil color measurements and to quantify the measurement of soil color. Its predictive value appears to equal or exceed that of commonly applied techniques.
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