wrb classification of polygenetic soils of sierra sur de oaxaca, mexico

Abstract

Complex polygenetic profiles form in mountainous tropical areas in Sierra Sur de Oaxaca, Southern Mexico. Some soils form on complex sediments: colluvial materials over deeply weathered clays. Depending on the genetic interpretation, they are classified as Chromic Luvisols or Thaptoluvic Cambisols. Other soils passed a long evolution in stable environments, and may be classified as Ferralsols

however, using only formal criteria. the soils should be Hyperferralic Umbrisols. Strongly acid materials with low extractable aluminum and high BS attest to the incorporation of less weathered rock in some profiles. Required analyses are sometimes inappropriate for deterring the placement of some soils.