“Terra Rossa” and Red Loams and Their Relation to Other Zonal Soil Types

In the regions adjoining the subtropics and in the subtropics proper a soil type is encountered the outstanding morphological characteristic of which is color. It is predominately red, but lt is not as pronounced as in laterites; it is of a lighter shade and in a great many areas, especially in the more humid regions, the yellow color is interdispersed. Because of the predominating red color of the soils there has been a tendency to identify a definite zone of red soils or red and yellow soils, as in the case of the soils in the Southeastern United States. And because of the color and geographic position these soils have been associated frequently with the process of laterization. And yet the geographic distribution of these soils the world over, as may be Judged from the available soil maps and scattered reports in the literature, brings them in contact with a number of soil types the zonal character of which is well known and from which we might attempt to ascertain their genetic relationships. Thus we find red earths merge into the podzolic brown (braunerde) and other forest soils in Prance and Italy. In Greece and Bulgaria they adjoin the chestnut brown soils, in Palestine—the brown and semi-desert gray soils, and in the United States—the brown forest soils and the Southern prairie. Prom the nature of this geographic position one could surmise that the soil forming processes operative in the regions of red soils would not be the same throughout all the areas of their distribution. Although no clear cut distinction has been made from this point of view the existing two divisions of red soils are suggestive. They are: 1) the Terra rossa and 2) the red loams.