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
2015 Annual Interpretive Summary
2014 was the first field year of the GRDC-supported micronutrient project. The objective of this research is to review and revise the Zn, Mn, and Cu management guidelines that were developed in the 1970s. This review is necessary because of the profound changes to cultivation systems, crop N and P nutrition, higher yields, and more intense and diverse rotations.
Four field experiments were commissioned in 2014 using a common design and protocols, with treatments based on the 4R principles of nutrient management. The treatments focus on application strategies so that alternative approaches to micronutrient management can be evaluated and included the use of seed dressings, granular fertilizer supplements (2 rates), fluid sources banded at seeding (7 rates), and foilar sprays (3 rates and two formulations). Appropriate nil controls were used, as well as luxury management that included seed dressings, banded fertilizer and foliar sprays. Growers are interested in using fluids, and this research aims to test the hypothesis that more even distribution with fluids can enable rates to be lowered.
Site 1 was at Harden (New South Wales, Australia) and had a DTPA-Zn soil test of 0.13 mg/kg, although this was quite variable across the site. Wheat was grown and all Zn applications resulted in increased tissue Zn concentrations, but there were no significant yield responses at this site. Site 2 was at Temora (New South Wales, Australia) with a DTPA-Cu soil test of 0.4 mg/kg (moderate), the site showed crop Cu deficiency symptoms in 2013. Wheat was sown at this site, but there were no treatment effects in crop growth, tissue concentration or grain yield.
Site 3 was at Farm Beach (South Australia, Australia) and had a history of Mn deficiency that is characteristic of this region which has high calcium carbonate concentrations in the soil. Plant tissue tests showed increased manganese concentrations, but there were no significant yield responses measured.
Site 4 was at Streaky Bay (South Australia, Australia) and the paddock was selected because Mn deficiency symptoms were seen in the established wheat crop. A range of foliar treatments were used (sulfates, EDTA chelates, lignosulfates, amino acid chelates) were applied at two rates. No responses to the applications were recorded in this experiment.
These types of non-significant results are not uncommon with micronutrient research, even though crops in 2014 had fair growing conditions during autumn and winter, but a harsh spring may have meant growth responses did not translate to yield responses.
In 2015, another series of experiments were planned and established. There are four experiments on Zn, two on Mn, and two on Cu. Yield results are as yet incomplete but tissue sampling showed good Zn and Cu responses.