Red Earths

Red Earths


(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.


References in periodicals archive ?
The main soil types of the area are broadly identified as Black Earths and Grey Clays (Vertisols) and Red Earths (Alfisols).
The Grey Clay, being inherently well structured and moderately fertile, is more resilient to cropping than the Red Earths of the area.
For soils low in clay, such as the Red Earths, good correlations between aggregation and SOM have been observed.
The detrimental impact of cropping on the inherently infertile and weakly structured Red Earth soils is severe and probably occurs soon after the soils are first cultivated.
There were declines in K of 86% on the Red Earth cultivated for 15 years and 66% on the Red Earth cultivated for [is greater than] 40 years.
Site Location WSA >250 [micro]m (%) Decline Red Earth Reference Warialda 43a Cropped (15) 20b 53 Reference Warialda 57a Cropped (40) 25b 56 Grey Clay Reference Warialda 64a, Lucerne (15) 36b 44 Sorghum (40) 39b 39 Reference Croppa Ck 33a Cropped (2) 35a -3 Cropped (43) 22b 33 Reference Moree, 54a Cropped (25) 24b 55 Black Earth Reference Warialda 49a Cropped (40) 14a 71 Reference Warialda 60a Cropped (25) 50a 16 Site Macropore K (mm/h) Decline(%) Red Earth Reference 399a Cropped (15) 55b 86 Reference 144a Cropped (40) 49a 66 Grey Clay Reference 507a Lucerne (15) 231b 54 Sorghum (40) 91b 82 Reference 216a Cropped (2) 219a -5 Cropped (43) 153a 29 Black Earth Reference 192a Cropped (25) 80b 58 Reference 377a Cropped (40) 213b 44 Reference 444a Cropped (25) 194b 56
Soils derived from these parent materials include lithosols, red brown earths, red earths, and earthy sands on the crests; and yellow solodics, yellow podzolics, red earths, and red brown earths on the lower slopes and drainage lines.
Soil types considered included red earths, solodics, and a range of cracking and non-cracking red, brown, grey, and black clays.
The red brown earths, red earths, chocolate soils, yellow solodics, yellow podzolic, and solodised solonetz have values of average PAWC ranging between 80 and 130 mm.
They reported RMSE ranging from 8 to 16 min for a red earth and a range of red brown earths in New South Wales.
Recharge is highest for the red earth and lowest for the grey clay.
Simulation Soil Rainfall Runoff landscape Grey cracking clay Yarraman 2 616 11 Red earth Stafford Gap 1 616 5 Euchrozem Lever Gully 1 616 7 Red brown earth Quirindi Creek 1 616 32 Simulation Recharge Transpiration soil evap.