What happens when you apply variable rate technology (VRT) in a season like 2024—hot, dry, and challenging? According to soil fertility expert Sean Mason and agronomist Peter Treloar, the results were anything but disappointing.
In our latest MSF FarmTalk podcast, we unpack the surprising performance of VRT in a drought year and why even low-yield seasons can reveal valuable insights for smarter, more cost-effective farming.
💰 Where Fertiliser Savings Were Made
With input prices still high and margins tight, one of the big wins from the 2024 VRT work was in redistributing fertiliser more effectively—not necessarily applying more, just applying it where it counts.
Sean explains:
“In a season like 2024, VRT really showed its value—putting inputs where they paid off and cutting back where they didn’t. In some cases, poor-performing zones could handle a cut in nitrogen, while sandy soils still responded well.”
Rather than blanket-applying fertiliser across paddocks, the project helped farmers strip back inputs in low-potential areas like stony ridges or acidic patches, and invest strategically in higher-return zones.
Peter reinforced this message:
“It’s not about buying more fertiliser—it’s about smarter use. Cut out your stone. Invest in your good ground. That’s where the return is.”
Mapping Lentils vs Cereals – What NDVI Can Reveal
A key discussion in the podcast centres around how NDVI maps differ between crop types, particularly in paddocks with underlying soil constraints like acidity or salinity.
Sean highlighted one striking example where a paddock planted to lentils in 2024 showed different NDVI zoning patterns compared to a cereal crop the year before. Why? Because lentils are far more sensitive to constraints like low pH and salinity.
“In some cases, the NDVI map for lentils effectively became a pH map,” Sean explained. “What looked like a high-performing cereal zone flipped to a poor-performing lentil zone because lentils just don’t tolerate acidity or salinity the way wheat can.”
This makes historical NDVI comparisons even more valuable—particularly when you rotate between cereals and legumes. Recognising where lentils fail but cereals thrive can help identify constraint zones and target lime applications more effectively.
Peter added:
“If you’ve got lentil and cereal yield maps from previous years, that contrast alone can help you pinpoint acidity problems. It’s a simple and cost-effective diagnostic tool.”
🔍 What It All Means for 2025
Despite the challenges of 2024, Sean and Peter are optimistic about what comes next. They agree that now’s the time to assess your paddocks, make a plan, and act on the insights you’ve collected over the past couple of years.
Whether it’s through:
Smarter zoning based on NDVI maps
Targeted lime applications in acidic patches
Seed rate adjustments for agronomic gain in zones
Or making the most of residual nutrients from 2024
—there’s plenty growers can do without spending more.
As Peter puts it:
“Start simple. Cut back where you know it’s not worth it. And reinvest where you’ll get the best return. That’s precision ag.”
🎧 Catch the full episode this Friday on the MSF FarmTalk podcast.
This episode is supported by the SA Drought Resilience Adoption and Innovation Hub, through funding from the Australian Government’s Future Drought Fund.
