Presentation on theme: "Nitrogen Use it or lose it Emission story Page 111 De Ferrier BCG, Ash Wallace DPI Vic."— Presentation transcript:
Nitrogen Use it or lose it Emission story Page 111 De Ferrier BCG, Ash Wallace DPI Vic
1. As a rule of thumb how much nitrogen does a wheat crop need to produce 1 t/ha of grain? 1.10 kg N/ha (22 kg urea/ha) 2.20 kg N/ha (43 kg urea/ha) 3.30 kg N/ha (65 kg urea/ha) 4.40 kg N/ha (87 kg urea/ha) 5.Unsure
2. When determining how much nitrogen is needed for a wheat crop what do you do? 1.I use a rule of thumb such as 40 kg N/ha per tonne of wheat 2.I apply what my agronomist tells me 3.I use a decision support tool such as Yield Prophet or an excel spreadsheet 4.I use soil or tissue tests 5.I use gut feel 6.I use a range of advice and tools
3. How do you rate your understanding of nitrogen losses? 1.Excellent 2.Good 3.Low 4.None at all
How much do you know about nitrous oxide emissions and their effect on productivity and greenhouse gases? 1.Nothing 2.A little 3.A bit 4.Quite a lot
How much nitrous oxide is lost from a cropping paddock in low rainfall areas annually? 1.0.1-0.5 kg N/ha 2.1-2 kg N/ha 3.10-20 kg N/ha 4.30-40 kg N/ha 5.50-100 kg N/ha
The global warming potential (GWP) of a gas measures the amount of heat it can trap in the atmosphere. Carbon dioxide has a GWP of 1. 1.10:1 2.50:1 3.298:1 4.310:1 5.450:1 What is the GWP of nitrous oxide compared to carbon dioxide?
The main levers that control emissions: What drives N 2 O losses? Soil water Soil nitrogen Crop management can alter these levers Minimising N loss is good for productivity = win win Soil carbon Soil temperature
Why are we measuring it? Limited research into the grains industry’s N 2 O emission contribution in low rainfall environments Govt policy is forever changing and uncertain (agricultural, environmental, political implications) Better communication needed to a wider audience Since the 2002-2009 drought more efficient and prescribed approach to nitrogen use. Nitrogen better match between crop demand and seasonal conditions. Need to inform accounting protocols – particularly legumes
GSR: 212mm Soil moisture: 42mm Sowing date: 19 June Variety: Derrimut Potential yield: 2.8t/ha To apply zero, medium and high urea rates and measure N 2 O fluxes from soil in a wheat crop the effect on wheat yield and quality Site: Rupanyup Nitrous oxide (N 2 O) losses from low rainfall environments How did we do it?
What did we find? Figure 1. N 2 O flux obtained (4, 6, 7, 14 September) before and after urea application at Rupanyup. Low N 2 O losses Peak levels were 4.5g N/ha/day 6 Sep = 0.3mm, 7 Sep = 8.13mm, 8 Sep =0.5mm, 13 Sep = 0.5mm 1 day prior 1 day after 1 week later 4 th Sep Urea 0 kg/ha 40 80
Dimboola grain prices @ December 3. Urea $620/t What did we find?
Nitrification inhibitors Can we do anything about it?
Improve nitrogen use efficiency Timing, N in front of rain Type of product Tools Soil test Rotations Can we do anything about it?
Take Home Messages Measured N 2 O fluxes are low in the Wimmera Mallee low compared to accounting methods. Ammonia likely to be more important from a productivity perspective. Products and tools are available to reduce losses. New products being investigated. Use it don’t lose it!!