More Profit from Crop Nutrition: Micronutrient Survey

Using data from regional soil tests, grain nutrient contents and a review of literature, the risk of plant micronutrient deficiencies (B, Cu, Mn, Mo, and Zn) was made across the Australian grains belt. The results indicate that the major micronutrient risk is from Zn deficiency and while Cu deficiency is not widely indicated, there are uncertainties about the risks associated with Cu. Future research should still focus on the deployment of these two micronutrients within cropping systems. Summary risk tables for each GRDC region were developed based on the relative area of each soil class. These were used for reference and discussion, and identified areas of uncertainty.

For the Northern Region the main soil micronutrient issue appears to be with Zn on Kandosols, Vertosols and Sodosols. There is uncertainty about Cu generally. For the Southern Region, the main soil types of Calcarosols, Sodosols and Vertosols have high risk of Zn deficiency, while Mn is likely to be a significant deficiency risk on these soils if they contain more than about 60% free calcium carbonate. For the Western Region, Kandosols and Tenosols are more significant than in the eastern states, although Sodosols is the major soil order, and low Zn is seen on these soils. The acid soil types, such as the more strongly acidic Tenosols, are likely to be at risk of Mo deficiency, while Mn deficiency is moderately likely Kandosols and Tenosols. This review has been incorporated into the Grains Research and Development Corporation investment plan for 2014-15 and future research will focus on the issues identified here.