Perth Laboratory – Public Seminar Series 2007

The effectiveness of airborne geophysical data for the management of dryland salinity

Simon Abbott
Curtin University of Technology
CRC LEME

Thursday 5 July 2007 at 3.30 pm, CSIRO Auditorium

Abstract

Over the last twenty years, farmers in Western Australia have begun to change land management practices to minimise the effects of salinity to agricultural land. A farm plan is often used as a guide to implement changes. Most plans are based on minimal data and an understanding of only surface water flow. Thus farm plans do not effectively address the site-specific processes that lead to land salinisation.

A project at Broomehill in the south-west of Western Australia applied a strategic approach to farm planning using a large suite of geospatial data that measured surface and subsurface characteristics of the regolith. In addition, other data were acquired, such as information about the climate and the agricultural history. Fundamental to the approach was the collection of airborne geophysical data over the study area. This included radiometric data reflecting soils, magnetic data reflecting bedrock geology, and SALTMAP electromagnetic data reflecting regolith thickness and conductivity providing information on the spatial distribution of salt storage in the landscape. When interpreted, these datasets added paddock-scale information of geology and hydrogeology to the other datasets, in order to make on-farm and in-paddock decisions relating directly to the mechanisms driving the salinising process. The location and design of surface-water management structures such as grade banks and seepage interceptor banks was influenced by the information derived from the airborne geophysical data.

To evaluate the effectiveness of this planning, one whole-farm plan has been monitored by the Department of Agriculture and the farmer since 1996. The implemented plan shows a positive cost–benefit ratio, and the farm is now in the top 5% of farms in its regional productivity benchmarking group. A high value of information is demonstrated for the geophysical information reflected in both farm plan implementation costs and long term productivity figures.

About the speaker

Simon Abbott is completing a PhD through the Curtin University School of Geophysics and the "Salinity mapping and hazard assessment" program of the Cooperative Research Centre for Landscape Environments and Mineral Exploration (CRC LEME). His research topic is "Information Products from geophysics for management of dryland salinity in Western Australia".

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