Physical Soil Constraints fact sheet

Physical Soil Constraints fact sheet

Published: 6 Jun 2022

The villains of hard subsurface layers in sandy soils.

Key points

  • Sandy soils commonly have physical constraints that reduce crop root growth and exploration and water use efficiency, which ultimately reduces yield.
  • Hardened subsoil layers within sandy soils vary in nature and distribution through the soil profile. They are typically categorised
    into two forms:
    • Traffic-induced compaction (cultivation pan) – soil particles bind together tightly due to the application of external forces, such as the weight of machinery, mainly when the soil is wet.
    • Natural subsurface hardening
      • Hardsetting – a reversible chemical process in which a hard layer forms as the soils dries out, restricting root growth, but softens on wetting
      • Cementation – an irreversible chemical process in which salts precipitate (solidify) and cause cementing, even when wet.
  • Understanding the differences between soil-hardening processes can assist with amelioration strategies and future planning.

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Region: National

GRDC Project Code: CSP1606-008RMX,