Physical Indicators of Soil Quality in Oxisols Under Brazilian Cerrado

Abstract

This paper presents a review on Latosols (oxisols) genesis, classification and use in tropical Brazil. Chemical, physical and mineralogical aspects are throughly discussed, as well as their relationship with soil use and management. Some problems of definition are considered for all types of Latosols recognized in the Brazilian System of Soil Classification. The role of clay minerals such as kaolinite, gibbsite and iron oxides (namely hematite, goethite, magnetite and maghemite) is discussed against the background of soil classification and soil fertility aspects. The ammount of trace-elements and the relationship between these elements (Mn, Cu, Zn, Co) and latosols genesis and classification is shown, illustrating the trend of higher values for those soils developed from mafic rocks and alike. The geographic distribution of latosols classes in Brazil (namely Ferriferous, Dusky-Red, Dark-Red, Red-Yellow, Yellow, Brown, Humic, Una variation and Pallid) is given. Finnaly, a general view on phosphorous adsorption for the various types of latosols is presented, illustrating the importance of the clay mineralogy as a primary factor of controlling P availability in these soils.