Summit Fertilizers Field Tour of the The East Pingelly trial sites, image taken mid-August 2021

East of Pingelly on Geoff Poultney’s property, Brett Coxon has two field trials examining manganese (Mn) and phosphorus (P) nutrition in Scepter wheat.

The Narrogin based Summit Area Manager hopes the season finish will be kind because the trials show real promise and should reveal valuable information for farmers in his area. Both trials have been established in the same paddock, in a sandy soil type that has a history of Mn deficiency. Geoff’s solution in the past has been to apply in-season Mn foliar sprays.

Available Mn applied in seeding fertiliser has some potential advantages. Young plants that can access it as soon as they emerge may establish faster and grow better, and it may relieve the pressure or necessity to apply this micronutrient post-emergent.

SUM21.04 at East Pingelly is one of a number of Mn trials Summit has this year and examines:

• a range of Mn rates;
• Mn applied in different chemical forms;
• supplied within MAP-based granules (compounded) or blended with MAP.

The trial also includes some foliar Mn applications.

“Plant testing at the site has indicated Mn compounded into MAP has an edge over blends at Mn rates of 1kg/ha and 3kg/ha,” Summit Field Research Officer, Jack Pages-Oliver, said.

“It’s possibly due to a better Mn distribution as the compound fertiliser has Mn in every granule. Mn uptake has also increased at higher rates. It will be interesting to see if these trends are observed in grain analysis, which will be done post-harvest,” he said.

SUM21.GP4, also on Geoff Poultney’s property, is part of GRDC’s NPK nutrition project. Summit has been involved with GRDC for the past five years investigating P responses in WA, including in soils where traditionally a P response would not be expected because conventional testing shows they have sufficient soil P levels.

Results in this project are challenging conventional thinking, and leading to a better understanding of factors that influence wheat yield response to P in current farming systems. Geoff’s trial site assesses Scepter wheat performance at different P rates.

“NDVI readings taken on August 12 in the trial showed plant biomass had increased with P rate up to 20kg/ha,” said Brett Coxon.

“Interestingly, Mn deficiency was noticeable in this trial in the low P treatments. This could be because more developed root systems supported by higher P rates helped the crop find more soil Mn.”

Results for these trials will available on our trials page once the data has been analysed post-harvest.

For more trial information growers can contact Brett Coxon on 0427 766 506.