SUM19-24: Potassium Strategies for wheat, Goomalling


To assess the response of wheat to applied potassium (K) rates, sources and placement.

Trial Details

Location: Haywood Bird Farms, Goomalling

Trial Size: 23 treatments x 3 reps = 69 plots.

Soil Type: Gravelly sandy loam

Crop Sown: Scepter wheat (dry sown), 90kg/ha, 13/05/2019

Table 1: Pre trial soil nutrient analysis


Figure 1: Treatment yield presented as the mean across 3 replicates. There is a significant yield response to applied K under these conditions
Figure 2: Yield K response curve shows a plateauing at 12kg K/ha. Mitscherlich function fitted
Figure 3: Average gross margin returns additional to nil control treatment (K0) showed a maximum additional return of 22% when 36kg K/ha was applied post emergence.

Key Messages

  • Goomalling experienced a decile 5 growing season rainfall in 2019 with three significant dry periods during the season. This rainfall pattern impacted yield potential in this trial.
  • Plant biomass was significantly influenced by K placement, with top-dressing or a combination of banding and top dressing increasing biomass.
  • There was a significant yield response to applied K under these rainfall conditions.
  • At rates greater than 24kg K/ha, banded K had a lower yield trend compared to other K strategies.
  • No significant difference between K supplied as MOP or SOP was found.
  • Higher rates of MOP and SOP banded may have been affected by high rates of product struggling to pass through the air-seeder at sowing.

For further information about this trial get in touch with local Area Manager Brayden Noble,, 0417 490 047.