The relationship of soil color to soil moisture tension

Color is an obvious and easily described soil characteristic. Probably man has always been conscious of soil color as he observed the color of good crop soils, those good for making brick, those that were good home sites and those good for gardens. Many such uses have related soil color to man's culture and economy.

Common terms such as "red dust" or "black mud" are used to describe soil out of place in a home, but important soil names have come from the colors. Chemosem (black earth), terra rosa (red earth), brown loams, black prairie soils and brown forest soils are examples of large soil areas named for their color.

Color is the most easily observed of soil properties and observance of color is very useful. If properly interpreted it is an indication of drainage, aeration, climate, age, parent material and to some extent, fertility.

Soil color is changed by soil moisture. The objective of this work was to investigate by trials the changes of soil color that might be associated with changes in soil moisture tension. If the soil color changes sufficiently over the available moisture range, then soil color could be used as a measure of available soil moisture.