Oxisols

{
  "id": "MLC-T-ENV-020058",
  "term": "Oxisols",
  "field": "Environment",
  "definition": "Oxisols are weathered soils that are low in fertility. They are most common on the gentle slopes of geologically old surfaces in tropical and subtropical regions. Their profiles are distinctive because of a lack of obvious horizons. Their surface horizons are normally somewhat darker than the subsoil, but the transition of subsoil features is gradual. Oxisols consist mainly of quartz, kaolinite, oxides, and organic matter. Both the structure and “feel” of Oxisols are deceptive. Upon first examination, they appear structureless and have the feel of a loamy texture. While some are loamy or even coarser textured, many have a fine or very-fine particlesize class, but the clay is aggregated in a strong grade of fine and very fine granular structure. To obtain a true “feel” of the texture, a wet sample must be worked for several minutes in the hands to break down the aggregates. The strong granular structure apparently causes most Oxisols to have a much more rapid permeability than would be predicted, given the particle size class. Although compaction and reduction in permeability can be caused by cultivation, the soils are extremely resistant to compaction and are so free draining that cultivation can take place soon after rain without puddling.",
  "subject": "Natural environments",
  "references": [
    "USDA Natural Resources Conservation Service Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys (1999)"
  ],
  "url": "https://mlchart.com/terminology/environment/oxisols/"
}