Field Research & Agronomy

Nitrogen, phosphorus and potassium in  wheat

AIM:

‍Part of a trial series investigating how cereals respond to nitrogen (N), phosphorus (P) and potassium (K) fertilizer under different growing conditions across WA.

With the purpose of improving yields and the advice offered to local farmers when selecting their fertilizer regime.

For further details contact your local Area Manager or the Summit Research Team

CONCLUSION

• NDVI data showed a strong growth response to increasing N and P rates, with greater growth when K was also incorporated.
• Harvest data indicated a positive yield response to applied N, P and K.
  The largest tonnage was 3.31t/ha having 40kg/ha of N, 18kg/ha of P and 20kg/ha of K applied.
  The smallest was 2.15t/ha receiving no fertilizer.
• Grain protein was low (8.5%-9.6%) and increased with N application, but decreased with K, probably due to N dilution.
  As grain yield increased Hectolitre weight were high (80.5kg/hL – 83.4kg/hL) and screenings were low (1.54%-3.30%).
• The highest revenue was $919/ha from applying N60, P18 and K0. The lowest revenue was $665/ha which had N60, P12 and K0 applied.
• Based on gross margin calculations and response curves the optimal rate for applying fertilizer to wheat under 2017 conditions is N40, P18 and K20.