Control of a major problem soil condition in the northern coastal rivers of NSW could soon be greatly improved by a new computer program being developed at Charles Sturt University.

Concerned at growing problems from acid sulphate soils for farming and nature conservation, CSU Honours student Liz Ash is “teaching” a computer model, an artificial neural network, about the climatic and soil conditions that cause acid sulphate soils to form along the banks of the lower reaches of rivers in the region.

Although only recently recognised, acid sulphate soils have caused massive fish kills in rivers along the NSW North Coast in the last decade.

Acid sulphate soils are formed when water rises through soils that are high in iron pyrites to the soil surface, where it forms sulphuric acid. High rainfall, flooding and rising tides can cause water tables to rise rapidly and empty acid into waterways.

The artificial neural network, which is based on the human brain and nervous system, “learns” the patterns and associations linking these soil and weather conditions to the acid soil problem, using actual field data.

When completed, the model can be used to quickly predict when sulphuric acid from susceptible soils will leach into nearby waterways. Although a computer model has been developed for controlled conditions on irrigated and artificially drained farms, this is the first model designed for more general application throughout the NSW Northern Rivers region.

The study uses data gathered on a sugar cane farm next to the Tweed River. Ms Ash recently completed this project as part of a Masters degree in Information Technology at CSU.