Should nitrogen rates be increased on blocks that produce very high yields?

  • High-performing sites are those blocks that perform well above the district yield potential (DYP) (Table 1) on a consistent basis.
  • In some cases, zones within a block may be high-performing rather than the whole block.
  • It is more likely for these sites to achieve high yields in the plant and early ratoon crops.
  • Record yields are substantially higher than the district yield potential in all regions (Table 1).
  • These are an indicator of what has been achieved under ideal conditions at a small number of sites, although average yields on these blocks are likely to be significantly lower.


Table 1. District yield potentials and record yields

  • High-performing sites generally have few soil constraints, are well managed and perform well when environmental conditions are favourable.
  • Due to the high yield, nitrogen use efficiency on these blocks may be better than poorer performing blocks on a farm or within a region. However, it is also important to optimise inputs on these sites to maximise profitability and minimise off-site effects.
  • Evidence suggests that the SIX EASY STEPS recommended nitrogen rate based on the district yield potential is unlikely to limit productivity at these sites.
  • There is a poor relationship between yield and optimum N rate (Thorburn et al. 2018) in sugarcane.
  • An assumption that big crops require higher nitrogen application rates than smaller crops may not be correct. Application of additional nitrogen will increase input costs and may not result in improved productivity, profitability or nitrogen use efficiency.
  • A risk associated with increasing nitrogen application rates on these sites is the potential to increase lodging and suckering and lowering CCS.

For these high-performing sites, the SIX EASY STEPS recommended rate should be applied unless evidence is available to support an increased nitrogen rate.


  • Reef regulations currently require productivity data that shows performance above the district yield potential in 3 of the last 15 years (refer to “Farming in Reef catchments – Prescribed methodology for sugarcane cultivation”).
  • From an agronomic perspective, a grower should determine whether there is a productivity and economic response to applying additional nitrogen fertiliser on these blocks or zones.
  • Ideally an on-farm trial comparing the SIX EASY STEPS recommended nitrogen rate to a higher rate should be conducted over several seasons.
  • This evaluation process needs to comply with reef regulations and a higher rate may need to be offset elsewhere on the block/farm.
  • A guideline for conducting on-farm trials is included in the SIX EASY STEPS toolbox.
  • Leaf testing also provides a valuable method for checking on the adequacy of nutrient inputs.


Papers published from the Australian Society of Sugar Cane Technologists annual conference are also available at


Version: April 2020


Disclaimer: In this disclaimer a reference to ‘SRA’, ‘we’, ‘us’ or ‘our’ means Sugar Research Australia Limited and our directors, officers, agents and employees. Although we do our very best to present information that is correct and accurate, we make no warranties, guarantees or representations about the suitability, reliability, currency or accuracy of the information we present in this publication, for any purposes. Subject to any terms implied by law and which cannot be excluded, we accept no responsibility for any loss, damage, cost or expense incurred by you as a result of the use of, or reliance on, any materials and information appearing in this publication. You, the user, accept sole responsibility and risk associated with the use and results of the information appearing in this publication, and you agree that we will not be liable for any loss or damage whatsoever (including through negligence) arising out of, or in connection with the use of this publication. We recommend that you contact our staff before acting on any information provided in this publication. Warning: Our tests, inspections and recommendations should not be relied on without further, independent inquiries. They may not be accurate, complete or applicable for your particular needs for many reasons, including (for example) SRA being unaware of other matters relevant to individual crops, the analysis of unrepresentative samples or the influence of environmental, managerial or other factors on production.

Site by Swell Design Group