Colour, in addition to being used i

Colour, in addition to being used in many soil classification systems as a discriminatory characteristic, has been used to provide evidence of matching between unknown samples and specific soil types (Dudley, 1975), and has been used in determining the role of environmental factors on soil composition (Barouchas and Moustakas, 2006; Bhadra and Bhavanarayana, 1997; Blavet et al., 2000). The relationships between individual soil parameters and colour has been investigated, particularly in relation to iron and organic matter (Barron and Torrent, 1986; Galvão
and Vitorello, 1998), but also to moisture content (Van Huyssteen et al., 1997), mineralogy (Sánchez-Marañón et al., 1997) and structure
(Sánchez-Marañón et al., 2004). Known relationships between changes to soil structure/chemical composition and soil development have been
used to extrapolate levels of development (i.e. the level to which soil-forming processes have altered the profile) in soils based on colour (Haidouti and Massas, 1998).