SUM19-25: Nitrogen x Phosphorus Rates, Goomalling.


This trial investigates the response of wheat to applied nitrogen (N) and phosphorus (P) ratesto determine a recommended fertilizer regime for local growers that maximises yield and profitability

Trial Details

Location: Haywood Bird Farms, Goomalling

Trial Size: 17 trts x 3 reps = 51 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: Grain yield and protein response. Yield (bars) increased with applied N and P. Protein (lines) increased with applied N. Data presented as the treatment mean across the 3 replicates.
Figure 2: Gross Margins. Protein content limited grain segregation and harvest yield drove profits. Clear jump in gross margins from applying 0 N to 40 kg N/ha. Individual gross margins presented as the treatment mean of the 3 replicates.

Key Notes

  • When P supply is limited, plants are unable to utilise additional N for plant growth and yield.
  • Harvest yield increased with applied N and P to trial maximum of 2.4 t/ha at 24kg P/ha and 120kg N/ha.
  • Grain protein content increased with applied N, with majority of treatments graded as ASW1.
  • Economic analysis showed the appropriate recommended fertilizer application rates under decile 5 rainfall conditions on gravelly sandy loam in the Goomalling area are 12kg P/ha and 80-100kg N/ha.

Contact local Area Manager, Brayden Noble 0417 490 047 for more details about this trial.