Therese McBeath1, Michael Moodie2, Rick Llewellyn1, Bill Davoren1, Willie Shoobridge1, Mick Brady2
1CSIRO Agriculture and Food 2Mallee Sustainable Farming
Key Word: nutrition, sandy soil, sands, yield, zinc, nitrogen
- The highest yield in 2016 at Loxton could be achieved with either 40 kg N/ha as urea or 20 kg N/ha as Zn-coat urea or Zn-enriched MAP.
- Compared to applying 20 kg N/ha as normal urea, using Zn-coated urea (20 kg N/ha) or Zn-enriched MAP with urea (20 kg N /ha) increased yield by over 20%.
- This is the second consecutive season that Zn coated Urea at sowing (20kg N/ha) has significantly increase yield compared to normal Urea (20 kg N /ha).
- Applying foliar Zn has not increased yield at this site in 2015 or 2016.
- Nitrogen was a key driver of wheat productivity again, with 40 kg/ha N at sowing increasing yield by over 20% compared to 20 kg/ha N at sowing, but water use efficiency remained poor on this sandy soil.
- There was also no benefit in delaying N application at Ouyen, however very high rates (60-80 kg/N ha) using higher late application rates increased yield on the midslope.
- In 2016 there was a large difference in yield between the midslope (2.90 t/ha) and the nearby sand dune (0.86 t/ha) at Ouyen which could not be closed through the addition of N,S and Zn to the sand.
How was the trial done?
In 2016 we established nutrition experiments at Loxton and Ouyen with a variety of treatments exploring the effects of nitrogen, sulfur and zinc on wheat productivity. The treatments included a range of N, S and Zn based treatments which were designed to address whether;
1) Constraints to productivity on sands could be managed by manipulating the nutrition package,
2) Early application of N is the most profitable option,
3) Zn is a constraint to yield and if the source of Zn is important, and
4) S is a constraint to yield and if the source of S is important.
We thank Bulla Burra (Loxton) and the Hastings family (Ouyen) for hosting the field sites. Thanks to Navneet Aggarwal for technical assistance. Thanks to Jeff Braun and Lou Flohr for discussions around trial design. Thanks to Colin Rivers and Ros Baird for preparing granular Zn fertilisers. This research is funded by GRDC and CSIRO Agriculture and Food (project MSF00003).