Darkan 2017

Nitrogen and phosphorus +/- potassium


To assess the response of wheat to nitrogen (N), phosphorus (P) and potassium (K) fertilizer application in the Darkan area, whilst evaluating the effectiveness of manganese (Mn) as a compound form (MnO) or as a blend (MnSO4).

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

Table 1: Soil Analysis
Fig 1: Yield Response to N & P


  • Despite the large biomass response to phosphorus during the growing season, harvest results were variable with considerably lower than expected yields.
  • Although a positive yield response was measured to applied N , the large improvement from P during the season had diminished and a decrease in yield was measured for applied K.
  • Under these conditions, ~40kg/ha of N and ~12 kg/ha of P without additional K, optimised returns.
  • A repeat of this trial under closer to normal yielding conditions would be valuable to determine optimal N, P and K nutrition considering the large responses during the season.
  • Summit will continue to research manganese sources and availability both in the field and at the glasshouse level.