Melissa Fraser

Artificial drainage and climate change affect soil physico-chemical properties and enhance structural decline in a saline vertosol in Upper South East (USE) South Australia

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Melissa’s research aims to understand the causes of structural decline occurring in saline Vertosols as they become sodic through the combined effects of declining rainfall and artificial drainage. Her research was motivated by the concern of land owners on this soil type in the Upper South East of South Australia. Reductions in watertable levels have occurred, along with a steady decline in annual rainfall, throughout this region since the early 1990s.

Lowering of the watertable has facilitated the leaching of salts from the uppermost horizons of the soil profile with the consequent development of sodicity (ESP >30% in most cases). It is hypothesised that the location, geographic extent and severity of sodicity are a result of a seasonally variable saline watertable, landform, variability in soil type and properties of soil horizons.

Melissa’s research falls into the CRC’s Program 2 research area.

Objectives:

• Determine the effect that artificial drainage and a decline in rainfall has had on soil physico-chemical properties in the soils at Keilira, USE SA
• To determine the factors that govern soil mineralogical variability in the soils at Keilira, USE SA
• Investigate the properties of soil horizons that govern the development or amelioration of sodicity
• To evaluate the change in landowner knowledge of sodicity and the soils in this region, and their management practices, to determine the effect of the extension program employed throughout this project.

For more information, email Melissa.