SUM20.25: Implications of P for Barley on High PBI Soil, Year 1 – Yield Response and Seed Nutrient Accumulation, Boyup Brook


The importance of seed quality at planting is often overlooked and seed nutrient content receives little considerations. It is opportune to evaluate the impact of varying phosphorus (P) supply and trace elements on retained Planet Barley seed performance at a high P fixing forest gravel site. Varying levels of nutrition were applied so that seed can be analysed and retained for use next year to assess the performance of varying seed nutrition levels. This trial hopes to provide further insight for improving on-farm P management.

Trial Details

Location: Rylington Park, Boyup Brook

Trial Size: 1.53m x 8m, 8 treatments x 3 reps = 24 plots.

Soil Type: Loamy sand.

Crop Sown: Planet Barley, sown 22/05/2020 at 80kg/ha.

Season Rainfall: 527 mm, BOM Newbicup, 54 mm above long-term average.

Table 1: Pre trial soil nutrient analysis


Figure 1: Harvest yield (bars) and grain protein (markers) presented as the mean across three replicates. There is a significant increase in yield with applied P.

Figure 2: Yield response curve to P rate applications with (triangles) and without( circles) trace elements. Mitscherlich function is fitted.

Figure 3a: Individual gross margins across the trial. Profits were influenced primarily by grain yield due to consistent grading.

Figure 3b: Individual gross margins additional to the nil P control (without trace elements). Data is expressed as a percentage value of returns additional to the nil P control.

Key Messages

  • Plant growth significantly increased with applied P.
  • Yield increased with increasing rates of P, ranging between 3.66t/ha and 7.77t/ha.
  • The application of trace elements had no significant impact on emergence, biomass or yield.
  • The most profitable treatment was 47kg P/ha applied without trace elements, returning $1840/ha.
  • The trial data indicated there are significant increases in profits to be made by a small investment in establishing strong foundation crop P status at sowing.
  • Seed will be retained, analysed for nutrient content and sown in 2021 to assess subsequent crop impacts.

For further information about this trial please get in touch with local Area Manager Chloe Turner