Resumo

SOTELO R., E. et al. History and Development of the Classification of Vertisols in the FAO System and Taxonomy. Terra Latinoam [online]. 2008, vol.26, n.4, pp.325-332. ISSN 2395-8030.

Vertisols are the most productive soils in Mexico and the world, because of their high natural fertility, which is the product of cation exchange capacity and high moisture retention. These soils are excellent for vegetable crops, such as onion, watermelon, tomato, and melon. Moreover, they produce the best yields of corn, wheat, and sorghum. However, there are no studies that integrate the existing knowledge of these soils. This study was conducted to 1) identify the different names that were given to the Vertisols during the evolution of soil classification; 2) describe their properties and characteristics for their identification and classification; and 3) determine the recent changes in the classification of Vertisols. The history of Vertisol classification in the Foodand Agriculture Organization of the United Nations (FAO) system or World Reference Base for Soil Resources (WRB) and Soil Taxonomy, two of the principal systems used in the world was reviewed. These soils currently known as Vertisols were called Pedocals, Rendzinas, and Grumosols, which were defined based on properties such as clay content (> 30%) and cracks; later on, in mid–twentieth century during the 6th International Congress of Soil Science, the name Vertisols was proposed and accepted, and it has been developed in the main classification systems. As a soil order, in the taxonomy of 1960 the Vertisols had two suborders, the 1975 four, and the 2006 six. With regard to the 1970 FAO system, the Vertisol unit had two Subunits and the WRB 2006 comprises 15 subunits.

Palavras-chave : Soil Science; soil order; soil suborder; unit and subunit.