Dispersive and sodic soils

Dispersive or sodic soils are common in the south-west agricultural area of Western Australia where they occur mainly as duplex or gradational profiles. Sodic duplex soils are particularly susceptible to waterlogging, as they are commonly on broad, flat landscapes with poor drainage. Other problems on these soils include reduced plant growth, increased erosion risk, and poor trafficability when wet. These soils are difficult to manage, and can have multiple constraints to crop and pasture growth. There are several options that improve soil structure, and potentially improve crop and pasture growth.

Articles

  • Dispersive soils are common in the agricultural areas of Western Australia, where they occur mainly as duplex or gradational profiles.

  • Dispersive (sodic) soils are common in the south-west agricultural area of Western Australia, where they occur mainly as duplex or gradational profiles.

  • It is not always easy to identify the degree of dispersion or sodicity in soils. The choice of suitable management depends on knowing the soil sodicity and whether dispersion is a problem.

  • Waterlogging causes clay to disperse in sodic soils, leading to soil structure collapse.

  • This page explains the factors that influence the degree of dispersion in sodic soils: soil structure (aggregate stability), cation exchange capacity, calcium to magnesium ratio, exchangeable sodiu

  • Soil aggregate stability is the ability of a soil to regulate the movement and storage of air and water throughout the soil profile.