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DEGRADATION AND CONTROL PROCESSES |
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Degradation process:
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Due to sealing and crusting.
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Description:
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When wet, soils with a structurally unstable surface horizon tend to form a surface seal, which is typically a few millimetres thick, on receiving the impact of raindrops or water from sprinklers. On drying, this gives rise to a surface crust. This process is due to the collapsing of aggregates.
Importance: great in structurally unstable soils.
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Soil functions affected:
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Plant nascence is affected, water infiltration is reduced and less water is available for plants. In contrast, surface runoff increases, as does the risk of erosion.
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Click on the image
Sealing and crusting: laminar structure of a
surface crust (J. Porta)
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Diagnostic criteria:
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Field soil study. Micromorphological study.
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Click on the image
Formation of a surface crust by splashing, seedlings
grow by taking advantage of cracks in the crust.
(M. A. Aran)
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Prevention and control:
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Prevent the direct impact of raindrops by providing a protective cover (vegetation or mulch). Improve the structure of the surface horizon by applying organic matter. Increase the frequency of sprinkler irrigation to maintain soil surface moisture, or use sprinklers which produce smaller drops.
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