ESTIMATION OF THE INFLUENCE OF SOIL-MOISTURE ON SOIL COLOR

Soil colour was expressed in terms of chromaticity coordinates instead of traditional Munsell notations which facilitated correlation with t he moisture content of soils. Spectral reflectance of twenty-one soil samples was measured in the visible region from saturation to air-dryn ess from which the colour coordinates for each soil at various moistur e levels were calculated. The data were transformed to metric lightnes s, metric chroma and Munsell values using the tables of Wyszecki and S tiles (1982). All the colour coordinates, metric lightness, metric chr oma and Munsell value were negatively correlated with the moisture con tent. For dark soils, the rate of change of colour parameters with moi sture is less compared to red and light coloured alluvial soils. An in teresting feature of the study is that all the colour parameters conve rged to a characteric value for a group of soils at zero moisture leve l (intercept), which will be useful to assess the moisture status of a soil in that group from the regression equations, if the colour of so il is estimated in terms of spectral parameters.