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.


28 Aug 2016

Zinc Trial Danadloo, 2015

Dandaloo (Narromine), NSW

Site selected based on paddock history and initial soil test results of <0.3mg Zn/ kg. This site was run in collaboration with David Harbison of DR Agriculture Pty Ltd.

1.1 Season summary

A dry February/March delayed any hopes of an early autumn. Late April rain gave some relief, however with marginal soil moisture (30-50 cm), much of the district was hoping on a good winter. Sown late May, following another 20 mm, the trial then received only 76 mm of in crop rain in total. Hot, dry and windy conditions experienced in early September literally blew away any chance of an average year. A very dry finish worsened the situation further, resulting in below average yields, some way below, for the district.

1.2 Trial details

The trial was sown in a 4 bay x 20 row completely randomised block design with each bay consisting of one replicate of the 20 treatments. Trial plots were sown at 12m and cut back to 10m in length, and were 2m wide. The 20 treatments are listed in Table 1.

Table 1: Treatment list for zinc deficient trial run in Dandaloo, NSW for the 2015 season.

No. Treatment Details

1 Seed dressing (120g Zn/ha)
2 Granular fertiliser at seeding (1kg Zn/ha)
3 Granular fertiliser at seeding (0.5kg Zn/ha)
4 Coated MAP product (0.5kg Zn/ha)
5 Fluid at seeding (1.0 Zn kg / ha)
6 Foliar spray sulphate (330g Zn/ha)
7 Foliar spray sulphate elemental = chelate (300g Zn/ha)
8 Foliar spray chelate (300g Zn/ha)
9 Foliar spray sulphate x 2 (330 + 330g Zn/ha)
10 Seed dressing + early foliar (120g Zn + 330g Zn/ha)
11 Nil Control
12 Luxury management (120g Zn + 1kg + 1.5kg + 330g Zn/ha)
13 Nil Control: Residual A
14 Nil Control: Residual B
15 Fluid at seeding (0.13 Zn kg / ha)
16 Fluid at seeding (0.25 Zn kg / ha)
17 Fluid at seeding (0.5 Zn kg / ha)
18 Fluid at seeding (0.75 Zn kg / ha)
19 Fluid at seeding (1.5 Zn kg / ha)
20 NIL - No Fert at all

1.3 Soil test results

All pre-sowing soil test results for each of the four reps are below 0.3mg Zn/kg. Although those in the top 0 – 10cm are very close to the target cut off for deficient field trial sites e.g. 0.29, 0.26, 0.25 and 0.26 mg Zn/ha.

Image taken at first YEB sampling (17 July 2015)

Image taken on 15th October 2015

1.4 Results

Establishment counts did not differ significantly between treatments suggesting that none of the treatments applied had an impact on germination, the site average was 99 plants/m2.
Plant growth measured as shoot dry weight was not significantly different between treatments, the grand mean was 35g / 20 dry shoots.
There were no statistically different treatment effects on yield at the end of the season, the site mean yield was 285 kg/ha.
Zinc tissue concentrations from the first youngest emerged blade sampled at Z14, were highest in the luxury management treatment (31 mg Zn/kg). 1kg Zn/ha as a fluid at seeding and granular fertiliser at seeding (1kg Zn/ha) had lower zinc tissue concentrations than the luxury management treatment (26 and 23 mg Zn/kg). Granular fertiliser at seeding (1kg Zn/ha), seed dressing, granular fertiliser at seeding (0.5 kg Zn / ha) and the coated MAP product did not statistically increase the tissue concentration of zinc relative to the control treatments.