Field Research & Agronomy

Phosphorus and Potassium on Pasture

AIM

‍To assess the most efficient way to allocate fertiliser spend in pasture near Manypeaks, WA

To see more detail of this trial contact your Area Manager or Summits Research Team

KEY MESSAGES

• A significant dry matter response was measured for nitrogen, but not for phosphorus or potassium.
• Nitrogen applied as urea in two applications of 100 kg/ha (92N, $100 /ha) generated the highest returns under these conditions.
• Phosphorus applied at $50 /ha with the addition of nitrogen produced the most dry matter.
• Summit will look to continue this trial over subsequent seasons to monitor the compounding effect of fertiliser treatments compared to where no fertiliser is applied.

CONCLUSIONS

• There was a significant response to nitrogen but not to phosphorus or potassium under these conditions (p<0.05).
• $50 /ha of P with the addition of N produced the highest total dry matter for the growing season.
• Under these conditions, the addition of urea at 100 kg/ha in two applications (92N) generated a significant dry matter response, resulting in the highest returns.
• For the most profitable N application, a balance between application when the requirement for extra feed is greatest and when growth conditions are more favourable need to be weighed against each other. Lower response efficiencies during winter when soils are cold and wet may be offset by the increased value of the feed generated.
• Summit will look to continue applications into subsequent seasons to measure the compounding effects of varying fertiliser applications.