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It may not be able to leap tall buildings in a single bound but Iron Man Gypsum (IMG) is a soil amendment that could be a superhero for agriculture and the environment.

A trial got underway this winter to test the effects of using the iron and gypsum rich product to improve the phosphate holding capacity of pasture soils. IMG, produced by Iluka in Capel, was applied at 20 and 60 t/ha during pasture renovation on a paddock on the Haddon Family dairy property in Yoongarillup. Many sandy soils used for farming on the Swan Coastal Plain have little capacity to hold phosphate, which can be easily leached or washed into waterways during winter. 

This trial explores how phosphate loss can be reduced using the IMG in high leaching conditions – keeping this nutrient where it is needed rather losing it to waterways. Nutrient leaching is monitored at the site using lysimeters which are coupled measurements of pasture productivity, soil nutrient storage and plant uptake.

From the farming perspective, if the phosphate is retained then less will be needed plus the amendment has benefits in terms of supplying sulfate and manganese.

The trial is a partnership between the Department of Water and Environmental Regulation, Yoongi Downs and Western Dairy. This was funded by Revitalising Geographe Waterways program (https://rgw.dwer.wa.gov.au/reducing-nutrients/) with technical support from the Regional Estuaries Initiative (https://rei.dwer.wa.gov.au/strategies/innovative-remediation/). 


Figure 1. Spreading IMG at 60t/ha prior to tilling in.

Figure 2. Second grazing of the trial plots.

Figure 3. Pumping out lysimeters catching leachates beneath the topsoil. 

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