Managing micronutrient deficiencies in cropping systems of eastern Australia
This project will address these increasing concerns and speculation in a three pronged approach for all six micronutrients named in the tender (Mn, Zn, Cu, B, Mo, Fe) for all cropping regions in Australia except for those in WA. This project will liaise closely with a separate bid being prepared by Dr Ross Brennan of DAFWA to address issues in WA specifically, should that bid be successful. This project will produce clear guidelines for management of micronutrient disorders for the major crops in the southern and northern regions of GRDC based on existing knowledge which has been objectively tested for its relevance to modern cropping systems and modernised for current technologies and economic circumstances where necessary.
IPNI-2014-AUS-020
2017 Annual Interpretive Summary
Between 2014 and 2017, a series of field experiments were undertaken to assess the effect on crop yield of multiple rates and application strategies of micronutrient fertilizers in soils deficient in the target micronutrients (copper, zinc, manganese, boron, and molybdenum). A total of 22 experiments were conducted in South Australia, Victoria, southeastern Queensland, and southern New South Wales. The results have been reported on the IPNI ANZ research project website http://research.ipni.net/project/IPNI-2014-AUS-020, as well as on the On-Farm Trials database https://www.farmtrials.com.au. The latter is a searchable on-line database of trial results from field experiments, including nutrition trials.
The overall conclusion for this body of work is that the current guidelines for soil and tissue tests are still relevant and effective for micronutrient management. However, some current interpretations of soil tests are causing issues - the suggested levels to avoid deficiencies are much higher in some lab reports than what the project has experienced from its field trials. The project concluded that these interpretations are creating false impressions of the extent and severity of zinc and copper deficiencies.
We found no evidence of a major increase in the incidence or severity of micronutrient deficiencies in the cropping zones. Fluid delivery of micronutrients at seeding is a valid management strategy but rates of the target micronutrients need to be the same as those used when they are included with compounded fertilizers. Generally, all sources of foliar micronutrients were equally effective.