Field Research & Agronomy

Phosphorus and Potassium on Biserrula Pasture

AIM

To assess the most efficient way to allocate fertiliser spend on biserrula pasture at Corrigin.

For full details of the trial contact your local Area Manager or research@summitfertz.com.au

BACKGROUND

Phosphorus and potassium fertilisers are utilised on pasture both to maintain soil levels and to improve productivity by allowing a higher stock carrying capacity.
Continual cropping can deplete the soil of nutrients and organic matter resulting in altered nutrient requirements when moving back into a pasture phase.
This trial looks to build data on the nutrient response of biserulla to phosphorus and potassium and to determine the most profitable fertiliser under these conditions.

CONCLUSIONS

• Very high summer rainfall was followed by a dry start to the growing season resulting in late pasture establishment.
  NDVI biomass and dry matter measurements were taken on the 29th August after rainfall in July and August had improved pasture growth.
  NDVI indicated a positive biomass response to $35-50 /ha of phosphorus, with $35 /ha of potassium and $50 /ha of P and K blended also considerably improving biomass
• No significant response to phosphorus or potassium was measured when total dry matter was calculated (p>0.05).
• Although phosphorus and potassium treatments did not drive a significant dry matter response, there was enough of an increase at $35 and $50 /ha to maintain similar returns to nil fertiliser whilst safeguarding soil nutrient levels for later seasons.
• Repeating this trial into subsequent seasons to measure compounding effects of varying nutrient applications, and during a season without delayed establishment, would be beneficial to build data and determine optimal fertiliser rates to maximise returns on biserrula.