Management strategies for improved productivity and reduced nitrous oxide emissions

The project aimed to trial, measure and demonstrate on farm practices and technologies to reduce agricultural greenhouse gas emissions. This project concluded on 30 June 2017.

Following is a summary of results from this project (prepared by Michael Straight, FAR Australia);

• N2O emissions from Australian grain cropping are highly variable due to large variations in soil, climate and management practices.
• N2O emissions from dryland cropping are particularly low compared with other grain systems in Australia.
• To optimise N efficiency and reduce N2O losses, we need a good understanding of soil N in the system, and therefore try to synchronise N supply with peak crop N demand to encourage greater fertiliser uptake.
• N loss through N2O emissions is highly dependent on seasonal variability and the soil moisture content at times of fertiliser application.
• The use of tactical N applications with the aid of a Greenseeker, allowed residual N from previous crops to be better identified and this allowed reduced fertiliser application without compromising yield.
• Delaying N applications maintained grain yield but allowed to make in season decisions around N application as the season progresses. This allowed more accurate forecasting of when crop demand for N is higher (stem elongation).
• In a wet season N losses will generally be higher. In these cases application of early N assisted to maintain the crop through wet periods and may be the best strategy in terms of grain yield and quality, but may also result in elevated N2O losses.

The detailed final report for this project is available for download here.

Summary information is also available in Riverine Plains Inc’s Research Compendium ‘Research for the Riverine Plains, 2017’.