The Color Of Soil
The first impression we usually have when we look at soil is the color. Depending on where you are, the color of bare earth can range from black to bleached white, with combinations of browns, reds, yellows, and grays in between.
"A black color most commonly comes from the presence of organic matter," he says. "Very light colored, usually not surface soil but subsurface horizons that would be white or bleached is usually a product of heavy leaching by acidic compounds. And then you get into the reds which are usually oxidized forms of iron."
Color can tell you something about the environment. Mottled colors are usually a combination of red and gray. These are soils that have intermittent flooding and because of the lack of oxygen, the iron compounds turn gray.
Color can also help you decide how to work with the soil.
"If you have grays or browns, usually we can find a way to manage those soils. There are crops that grow better in soils with lower organic matter, there are crops that grow very well in sandy soils which have a very light color," he says. "So, you can either match the crop or your management practices to that soil and make it productive."
Although it’s tough to change the color, adding organic matter and nutrients where needed is beneficial to soil structure and productivity.
Use the Munsell color chart for a scientific approach to soil color.