SUM20.27: Establishment Phosphorus Compounds and Nutrient Supply for Wheat Crop Production – Large Plot Trial, Yornaning


This trial compared 3 different cropping fertilizers that vary significantly in their phosphorus (P) content. MAPSZC (at 19.8% P), Vigour (12% P) and AllRich (with only 8.7% P) were applied at a range of different P rates and the impact on Magenta Wheat yield (and gross margin returns) investigated.

This trial also aims to assess the effectiveness of trial methodology of sowing a cereal crop through pre-placed strips of P compounds, as well as comparing remote and on-ground biomass measurements for in-paddock variability in growth and yield.

Trial Details

Location: Yornaning

Trial Size: 4.5 x 100 metres, 10 treatments 3 x replicates =30 plots.

Soil Type: Loamy sand.

Crop Sown: Magenta wheat, sown 24/05/2020 at 65 kg/ha.

Season Rainfall: 254 mm, BOM Narrogin, 95 mm below long-term average.

Table 1: Pre-trial soil nutrient analysis


Figure 1: Harvest yield (bars) and grain protein (lines) presented as the mean across four replicates. Yield increased with applied P in all products.

Figure 2: Individual gross margins across the trial. Returns were greatest when 12kg P/ha was applied for each product.

Key Messages

  • In-season biomass readings done by hand using a handheld Greenseeker® and through high-resolution satellite imagery indicated that biomass was not significantly affected by increasing P rates but was primarily influenced by variations insoil type across the trial.
  • Yield increased with increasing rates of P, ranging between 2.73t/ha and 3.06t/ha.
  • The most profitable treatment was 12kg P/ha applied as MAPSZC, indicatively returning $805/ha.
  • The higher-analysis products, MAPSZC and Vigour, had higher yields and higher gross margins than the low analysis product AllRich, however differences between products was not significant.  
  • Using lower analysis products (such as AllRich) can have logistical disadvantages, in terms of increased storage demand and higher freight costs. In addition, blockages to seeding equipment can become more likely when using lower analysis products, due to the higher rates required.

For further information about this trial please get in touch with local Area Manager Brett Coxon