The answer is in the soil

There was research on Professor Bill Hogarth's mind when he took up his appointment as Pro Vice-Chancellor of the Faculty of Science and Information Technology at the University of Newcastle in 2002.

Since then, as well as managing a large faculty, Hogarth has published 23 papers, contributing to a significant base of more than 100 journal publications over his academic career.

"Research is a very important part of the University profile, so it is imperative as the head of a faculty that I am an active researcher."

A mathematical modeller who applies his skills and knowledge in soil physics, Hogarth came to Newcastle from Griffith University, where he was Dean of the Faculty of Environmental Sciences.

Hogarth’s work lies in the mathematical modelling of wind erosion, and solute and water transport on the surface and sub-surface of soils.

"Most of my work in soil and wind erosion is predictive modelling using mathematics to help understand fundamental physical processes," he said.

Hogarth said his mathematical modelling was most critical in its predictive role.

"In the case of wind erosion, we present physical data in graphical form. We try to simulate this form through the solution of a sequence of equations representing the fundamental physical processes," he said.

Hogarth said mathematical modelling provided a context in which researchers could ascertain the current status of erosion and predict what might happen in the long term. The wind erosion work takes data from 10 metre towers in outback Queensland and, using spatial modelling, the team predicts soil profiles.

This also gives Hogarth an idea of where the soil comes from and where it might finish up.

Hogarth collaborates with researchers from Griffith University, Cornell University in the United States, and colleagues in Switzerland to model physical systems in the first instance and then solve them numerically.

He said the majority of his mathematical modelling was applied to the physical consequences of water impacting on soil.

"Rainfall or irrigation, and its subsequent infiltration into unsaturated soil, is extremely important for plant growth because in addition to its hydration qualities, water also carries vital nutrients for healthy crops," he said.

"On the negative side, water infiltration can often carry harmful soluble chemicals so deep they enter and pollute groundwater supplies being used by humans and animals. This groundwater often enters lakes and streams, resulting in death to fish and plant life."

Additionally, if the rate of the water falling on the soil is faster than the rate at which the water can be conducted in the soil, small ponds occur on the surface and run-off begins. The development of blue-green algae is an example of how nutrients from groundwater or surface run-off can enter and affect water bodies.

Modelling water infiltration into soil and predicting soil loss through erosion is important for managing agricultural production and its environmental consequences.

Hogarth said mathematical modelling was also helpful in managing groundwater and water supply from catchment areas and is key to the design of irrigation systems.

While the Professor shrugs off the ‘greenie’ label, he said an interest in the environment was the springboard for his work.

"My work is in environmental modelling but I am a pragmatist. We have to look at how we preserve and sustain the environment and, at the same time, be realistic.

"People need to inhabit the land and we need to use the water – it is all about finding the right balance."