N-rich strips are used both by fertiliser companies and farmers to determine whether or not the surrounding crop is nitrogen deficient. Due to the increased biomass, vigour and crop greenness of these strips, they tend to lead to farmers applying more nitrogen to the surrounding crop.

As part of its Nutrient Use Efficiency project, Wheatbelt NRM funded LivingFarm (York) in 2015 to determine the actual yield and economic benefit of these N-rich strips.

This was deemed necessary as N-rich strips are often never harvested by small plot machinery; so never have accurate final yield determined or economics analysis completed.

Trial Snapshot:

• Wheat, barley and oats crops sown at three different sites in York with N-rich plots of 80L/ha and 160L/ha Urea Ammonium Nitrate (UAN) applied post seeding. Untreated control plots were included at each site.
• Yield results for wheat and oats showed no significant difference between N-rich plots or control plots (2015’s dry finish may have resulted in underutilisation of nitrogen at these trial sites).
• Yield results for barley showed significant yield increase where UAN was applied, however, no difference between the 80L/ha and 160L/ha UAN rates.
• Grain protein significantly increased with higher UAN rates in wheat and barley. No significant response in oats.

The final economic analysis completed for the trial plots supported the theory that applying high levels of nitrogen to maximise yield doesn’t always lead to the most profitable bottom line for farming businesses.

Grain and fertiliser prices, protein bonuses, rainfall to date and long-term weather forecasts should all be taken into consideration when deciding on in-season nitrogen applications. Chase the profit not the yield!

Resources

WNRM's Soil Health & Nutrient Use Efficiency - https://www.wheatbeltnrm.org.au/soil-tests

UWA's Living Farm - http://www.livingfarm.com.au/