Micronutrient Field Evaluations

During 2011 and 2012, six micronutrient field experiments were undertaken with cooperators from across Victoria. Sites selected on the basis of soil tests and cropping history were likely to respond to either Cu or Zn. The experiment in the Mallee investigated the effect of different presentations of Cu on what would be expected to be a Cu responsive site. There were responses to Cu when compared to an unfertilized control, but the yield of the superphosphate alone treatment was significantly lower than the untreated control, but no explanation is immediately apparent for this result. Three experiments were undertaken on the Vertisols in the Wimmera, at Horsham (2011), Nhill (2011) and Longerenong (2012). No significant responses were seen with added Cu or Zn at these sites. Two experiments were undertaken in the high rainfall zone of the western District, and neither of these showed significant yield responses to Cu or Zn applied as foliar supplements.

Grain analyses of the 2012 experiments will be reported when the results of these analyses are available. These results highlight the difficulty in identifying sites where micronutrients are limiting wheat yields, although the use of both foliar and at-seeding treatments are quite common across a wide range of cropping systems. It is uncertain if this approach is considered as "insurance" or if responses are seen in paddocks that are not reflected in the experiments reported here. ANZ-14