In the fifth year of our lime x potassium (K) trial held in Cascades we are still seeing the benefit of applied K every season in low potassium areas. Plant testing conducted on 7 July, showed that treatments 4, 5 and 8 that received K at the start of the season whether it was supplied by K-Till Extra or by Muriate of Potash top-dressed prior to seeding should have enough K to maximse yield, while the other treatments 3, 6 and 7 that didn’t receive potassium in 2017 had marginal levels. Treatments 6 and 7 (residual K) didn’t show any deficiency symptoms and scored quite well in visual appraisals, but plant testing indicated hidden hunger that  may be yield limiting come seasons end.

There was a yield response to lime in 2016 barley but this year there have been no visual responses or effects in plant test results. Earlier seasons have shown that removing K inputs to focus on pH levels with lime inputs was unprofitable and unsustainable. Gross margin analysis showed that the extra profitability from the K applications through increased production well and truly covered the cost of the lime application.

Key messages

  • Regardless of crop type, K can be profitable when applied where levels are low
  • If levels are low, annual application are most profitable
  • Maintaining K inputs when undertaking liming programs is critical to maximise profitability
  • Plant testing and not visual symptom diagnosis is key when assessing crops in field 

lime x potassium trial
Plot 4 100 kg/ha K-Till Extra (13K) Vs 72 kg/ha Agstar Extra (0K)

Jeitz lime x potassium results table

*60 kg/ha applied in 2013, 2014, 2015 and 2016

** 60 kg/ha MoP applied in 2013, 2014 and 2015

Scott Nelson
By Scott Nelson
- Agronomy Lead
Scott was raised in Narrogin on a farm at Nomans Lake. 

After a stint on the family farm, Scott also worked for several local rural and merchandise businesses and his own retail sporting business before joining CSBP in 2010, as an Esperance Area Manager. Scott’s knowledge and passion for crop nutrition has seen him move into his most recent role of Agronomist for the Esperance and Eastern regions.

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