Field trials have commenced in the grainbelt as part of a large, collaborative research project to optimise fertiliser use on crops grown on soils that have been ameliorated with deep ripping or inversion tillage.
While there has been increasing interest in practices like mouldboard ploughing, rotary spading, disc ploughing and deep ripping, relatively little is known about how they impact soil nutrient supply.
The Department of Primary Industries and Regional Development is leading the ‘Nutrient re-distribution and availability in ameliorated and cultivated soils in the Western Region’ project, announced earlier this year by the Grains Research and Development Corporation.
The department is also working with Curtin University, Murdoch University, the University of Western Australia (UWA), the CSIRO and MapIQ to deliver the project.
Department plant nutritionist Craig Scanlan said field trials established this year would help researchers gain a better understanding of the long-term effect of rotary spading and deep ripping on soil nutrient availability and the impact on yield responses to fertiliser.
“Our trial at Meckering will provide us with a better understanding of how deep ripping changes the yield response to nitrogen (N) applied this year and if it has any impact on the residual benefit of this N in 2019,” Dr Scanlan said.
“Another trial established at the department’s Badgingarra Research Facility has been designed to measure the effect of the type of crop residue buried by inversion tillage in 2019 on the grain yield response to nitrogen fertiliser.”
Further paddock scale wheat trials have also been set up this season to gain an insight into how the yield response to potassium (K) fertiliser varies spatially on ameliorated soils.
Dr Scanlan said the trials at Mingenew, Meckering and Esperance were being undertaken on paddocks where Controlled Traffic Farming (CTF) was being used.
“These paddocks are like massive field trials, where we are using CTF to accurately place our fertiliser treatments and measure the corresponding yield data,” he said.
“The variation in the yield response to the potassium treatments across the paddocks will be used to target areas for soil sampling, to investigate which soil factors are influencing the yield response to K fertiliser on ameliorated soils.
“As a result of this work, we will be able to provide some guidance on how growers should be doing their soil testing on ameliorated soils.”
The department’s research complements two other projects, one led by UWA on increasing profits from fertiliser inputs in a range of emerging crop sequences and the other by the CSIRO to improve soil sampling methods to better predict soil nutrient availability and supply.
Together, the research projects will quantify how yield response to fertilisers in ameliorated soils compared to current no-till practice.
The outcomes of this work will be used to update existing decision support systems for fertiliser use.
Jodie Thomson/Megan Broad, media liaison
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