San Martinho sugarcane plantation
Soil profile of Oxisol. Oxisols are an order in USDA soil taxonomy, best known for their occurrence in tropical rain forest, 15-25 degrees north and south of the Equator. They are classified as ferralsols in the World Reference Base for Soil Resources; some oxisols have been previously classified as laterite soils.The main processes of soil formation of oxisols are weathering, humification and pedoturbation due to animals. These processes produce the characteristic soil profile. They are defined as soils containing at all depths no more than 10 percent weatherable minerals, and low cation exchange capacity. Oxisols are always a red or yellowish color, due to the high concentration of iron(III) and aluminium oxides and hydroxides. In addition they also contain quartz and kaolin, plus small amounts of other clay minerals 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 particle-size 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.
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San Martinho sugarcane plantation
Soil profile of Oxisol. Oxisols are an order in USDA soil taxonomy, best known for their occurrence in tropical rain forest, 15-25 degrees north and south of the Equator. They are classified as ferralsols in the World Reference Base for Soil Resources; some oxisols have been previously classified as laterite soils.The main processes of soil formation of oxisols are weathering, humification and pedoturbation due to animals. These processes produce the characteristic soil profile. They are defined as soils containing at all depths no more than 10 percent weatherable minerals, and low cation exchange capacity. Oxisols are always a red or yellowish color, due to the high concentration of iron(III) and aluminium oxides and hydroxides. In addition they also contain quartz and kaolin, plus small amounts of other clay minerals 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 particle-size 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.
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