soil

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…not an index of fertility. Soils having a red or reddish-brown hue usually contain a large proportion of iron oxides (derived from the parent rocks) that have not been subjected to excessive humidity. Red color in a soil, therefore, is generally an indication that the soil is well drained, not excessively humid, and fertile. This generalization is particularly true in the southeastern U.S. but is not always true in other parts of the wor