Don't put up with denitrification
ENTEC® is used by many cane growers to help minimise one of the most significant nitrogen loss pathways in cane – denitrification.
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Not only can denitrification leave crops without the nitrogen they need to achieve their productive potential, it can also contribute to greenhouse gas emissions.
The issue is not limited to a particular soil type or region. It can happen in any cane crop where nitrate is present and the soil’s pore spaces fill with water.
What is denitrification?
In simple terms, denitrification occurs because soil microbes require oxygen. When all the small air voids in the soil are taken up with water instead of air, they find it difficult to get oxygen.
In these situations, they move their focus to breaking down nitrate, which is made up of one part nitrogen and three parts oxygen.
Di-nitrogen and nitrous oxide is released to the atmosphere as the microbes consume the oxygen from nitrate. Denitrification events can occur whenever the conditions are right and this is often multiple times in one season.
They can happen due to prolonged wet weather after fertiliser application, a single major rain event, or even unexpected rainfall after irrigation. Denitrification losses can occur even with small rainfall events if the soil is already moist.
What is at risk?
The size of denitrification losses will vary from season to season, but it is generally thought to be a major nitrogen loss pathway in cane.
Take the example of the trial conducted in a plant crop near Mackay in the 2010-11 season1, where above average rainfall in the six months after fertiliser application meant the ground was saturated for prolonged periods.
Nitrous oxide losses were measured and they showed that the ENTEC urea treatment reduced overall nitrous oxide losses by 4.2 kg/ha compared with urea.
For more information
Feel free to contact me on 0428 111 471 or rob.dwyer@incitecpivot.com.au.
Rob Dwyer
Tropical Systems Agronomist
Incitec Pivot Fertilisers
soil under different fallow and nitrogen fertiliser management regimes’ by WJ
Wang1, B Salter2, SH Reeves1, TC Brieffies2, J Perna2. (1 Department of Environment and
Resource Management, Dutton Park 2 BSES Limited, Mackay).