(Russian, krasnozemy), a type of soil formed under broad-leaved forests in a moist subtropical climate and, partially, in tropical savannas.
Typical features of red earths are a high content of sesqui-oxides (ferric and aluminum oxides) and a very low content of bases and silica. A warm, moist climate promotes intensive processes of rock disintegration, decomposition of aluminosilicates, and loss of calcium and magnesium. Ferric oxides give red earths a bright reddish or orange color. The most typical red earths are found on gentle slopes of 8°-10° to 20°-25°; on steep slopes red earths are weakly developed, shallow, and usually strongly eroded. Strongly marked horizons of washed-out and washed-in material are usually not observed in the profile of these soils. The reaction of red earths is acid or weakly acid (pH of a water extract is 5.0-5.7). They usually have a clayey loam or clayey texture. A distinction is made between the red earths of subtropical forests and those of tropical savannas.
Red earths are widespread in the central and southeastern parts of China, in Vietnam, Japan, eastern Australia, the southeastern United States, Brazil, Uruguay, Africa, the island of Madagascar, southern France, Italy, Spain, and other European countries. In the USSR they are found on the eastern shore of the Black Sea (in the Georgian SSR) and on the southwestern coast of the Caspian Sea (Azerbaijan SSR). Tea, tobacco, grapes, and citrus fruits are among the crops grown on red earths.
M. N. SABASHVILI