The Department of Primary Industries and Regional Development (previously Agriculture & Food) have partnered with CSIRO to map the current extent of salt-affected land in the south-west agricultural region. Landsat satellite imagery is being used to repeat the Land Monitor project that produced maps of salt-affected land in 1988–92 and 1996–2000. The goal of the project is to determine if dryland salinity is increasing and where the increase is happening.
The first draft of the 2016-2018 Land Monitor salinity map is now being evaluated. The map shows four categories of low productivity land that may be salt-affected. The map does not distinguish between moderately and severely salt-affected areas. An example of the draft salinity map is shown below.
Work will identify areas incorrectly mapped as salt-affected and areas that are known to be salt-affected which do not appear on the draft map. Feed-back will also try to reduce the inclusion of non-productive land that may be mis-classified as salt-affected in the draft maps such as bare soil, water logging and farm infrastructure. Capturing this information will help increase the accuracy of the map which uses multiple years of Spring imagery to define the areas of consistent low productivity.
DPIRD staff displayed the draft Land Monitor map at Wagin Woolorama on the 6th and 7th March and landholders were keen to compare the map with their local knowledge. DPIRD had planned to display the map at all the major agricultural shows, however Mingenew Midwest Expo and Dowerin Field Days have already been cancelled due to the COVID-19 risk. To the best of our knowledge, Newdegate Machinery Field Days will still run in September. Despite being unable to show the draft map at the agricultural shows, DPIRD still need to provide feedback to improve the map. DPIRD staff will be out and about field checking the map between now and spring, our engagement with landholders will be governed by cropping work schedules and advice on COVID-19 risk.
A new map of the extent and trends of salinity is expected in mid-2021.
Article by Dr Paul Raper | Research Scientist
Water Science, Agricultural Resource Management and Assessment Sustainability and Biosecurity
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