Saving money can save the planet yielding top crop

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Nitrogen fertilisers can be the single largest input cost for grain growers seeking maximum yield.

New work by Agriculture Victoria researchers found that a better understanding of soil background nitrogen levels can help farmers make better decisions about the nitrogen requirements of their crops.

The ‘Reducing on-farm N2O emissions through improved nitrogen use efficiency in grains' research project involves nine sites at seven localities in the Wimmera, North Central as well as the Glenelg Hopkins CMA regions.

The study covers a range of cereal-based cropping systems on different soil types and climatic zones (low, medium and high rainfall) as well as irrigated cropping.

Research undertaken in the Glenelg Hopkins CMA region found useable stores of nitrogen in the soil profile can be high, often exceeding 200 kg N/ha, and high rainfall zone farmers can apply rates of nitrogen higher than required when the background nitrogen levels are not considered.

This is a cost farmers are not recouping in improved crop performance.

The Agriculture Victoria study identifies opportunities for farmers to reduce nitrogen fertiliser applications and save money. Another benefit is the reduced risk of soil nitrogen loss to the atmosphere as nitrous oxide (N2O). It is estimated that up to 15% of applied nitrogen fertiliser is lost to the atmosphere as N2O.

While 2016 was notable for record breaking rainfall regionally, 2016 was the hottest year on record globally. The previous hottest years being 2015 followed by 2014.

This heating trend and increase in climate variability, has been attributed to rising levels of greenhouse gas in our atmosphere. N2O is a potent greenhouse gas 300 times more effective at trapping atmospheric heat than carbon dioxide. Reducing nitrogen loss from soils can reduce Australia's greenhouse gas emissions.

Findings from the Agriculture Victoria study show nitrogen use efficiencies can be achieved though pre-sowing testing for soil nitrogen and factoring useable nitrogen stores into calculations of crop nitrogen fertiliser requirements and, in the high rainfall zone, nitrogen utilisation may be improved by delaying application until the late curing/early booting stage.


While the three-year project will be completed in July 2017, final crop samples are now being collected. Final results maybe be available as early as February 2017. Field day events to make the findings available to farmers are planned for April 2017.

The project is co-funded by the Australian Government's, Action-On-The Ground Program and DEDJTR in partnership with Glenelg Hopkins, North Central and Wimmera CMAs.

For more information about the project contact project leader Senior Scientist Roger Armstrong at Agriculture Victoria, Roger.armstrong@ecodev.vic.gov.au  or Richard Murphy at Glenelg Hopkins CMA,  r.murphy@ghcma.vic.gov.au .

1.	Dr Oxana Belyaeva (Agriculture Victoria) discusses Lake Linlithgow trial results at the Southern Farming Systems 2016 Winter Crop Walk. (Image courtesy of SFS)