Spectroscopic analysis of soil colour

Summary

The preliminary investigations reported in the foregoing pages may be summarised thus:-

• 1. The colour factor of a soil has been so far not fully exploited in its relation to soil genesis and characteristics. This is because the understanding of soil colour has been imperfect.

• 2. The use of the spectrophotograph offers a new approach for the precise investigation of soil colour and for the correlation of soil characteristics with soil colour.

• 3. A study of the absorbed and dispersed light intensities of a soil has shown that soil colour can be investigated as a continuous variable.

• 4. The soil colour, as revealed by the colour analysis with the spectrophotograph, appears to be determined more by the inorganic components of the soil than by the organic.

It is to be hoped that this new and interesting approach introduces a new and more precise factor in explaining what soil colour is, to what extent it is due to absorption, to what extent it is due to scattering and reflection of light and in ascertaining soil genesis or formation under the influence of climate and geology. From the theories on the scattering of light, it may be possible to investigate the distribution of particle size and its effect, base exchange in relation to double layer of soil colloids or behaviour of soil colloids as acidoids, basoids and saloids.