Nitrogen Use (In)Efficiency In Wheat – Key Messages From 2014-2017

GRDC - Richard Daniel, Rachel Norton, Anthony Mitchell, Linda Bailey, Denielle Kilby and Branko Duric, Northern Grower Alliance

Type: Research Paper
Knowledge level: Advanced

Farm Table says:

The authors of this paper note in the conclusion: "This series of trials over 4 cropping seasons and 14 trial locations has provided results that question some of our current management practices.
  • It has supported the general N grain recovery ‘rule’ applied in N budgeting of 40-60% of available soil and fertiliser N but highlighted a large difference in efficiency between the two sources.
  • It has highlighted the poor efficiency of fertiliser N grain recovery in the year of application with mean levels of ~15-20% applied N recovered in grain at common commercial rates (50 -100 kg N/ha).
  • The relatively shallow and slow movement of the applied N is likely to be a major cause for this inefficiency.
  • Consider non-cereal options in paddocks with very low soil N levels.”.
Please access the full paper via the link below if this research interests you.

The take home messages from this GRDC funded research are below. Please access the full paper via the link below for methodology, references, acknowledgements and discussion.

Take home messages from the paper include:

  • Over the 14 trials from 2014 to 2017, the efficiency of nitrogen (N) grain recovery from soil N was ~4 times that of fertiliser N that was applied in the year of cropping.
  • Maintaining high soil N levels is critical for cereal production efficiency due to the poor fertiliser N grain recovery.
  • Testing of grain, stubble and soil at harvest was able to account for a mean level of ~79% of the applied fertiliser N over 23 comparisons.
  • However in 4 of the 23 comparisons, testing only accounted for 30-50% applied fertiliser N.
  • The majority of the additional N at harvest was recovered in the soil and averaged ~65% of the applied quantity.
  • The slow and shallow fertiliser N movement in soil is likely to be impacting on grain recovery efficiency.
  • Strategies to get fertiliser N deeper, more quickly, may provide useful efficiencies in uptake and reduce potential losses.
  • Strategies that can improve N contribution from the legume phase will be highly productive.
  • Fallow N fertiliser applications are likely to provide a benefit over at planting application in years with low in-crop rainfall.

2018 - Australia - GRDC - Richard Daniel, Rachel Norton, Anthony Mitchell, Linda Bailey, Denielle Kilby and Branko Duric, Northern Grower Alliance
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