Research into reducing the reliance on nitrogen fertilisers

On 7 December, participants gathered for an open day hosted by the Tasmanian Institute of Agriculture (TIA) at its dairy research facility. 

The facility – located at Elliott in Tasmania’s north-west – has undergone a major upgrade, thanks to the commissioning of a new dairy and research setup. The open day provided farmers and industry members with the opportunity to see its transformation.

These changes include moving the milking area from one side of the farm to another as well as installation of a new dairy, which has changed from a swing-over herringbone to a rotary. Additionally, there has been installation of new facilities to help different on-farm research to take place, including work on dairy beef, low emissions feed and virtual fencing. 

Dairy Australia – in partnership with TIA – is currently undertaking a five-year research project at this site addressing the growing interest in reducing the reliance on nitrogen fertilisers used in pasture production. The project is known as Dairy HIGH (short for High Integrity Grass-fed Herds) and is in its second iteration.

By reducing reliance on synthetic nitrogen fertiliser used in pasture production, the Dairy HIGH 2 project aims to deliver significant cost savings for farmers, improved milk production efficiencies and important environmental outcomes.

It is also helping farmers address growing concerns including the high costs of nitrogen (N) fertiliser and the environmental footprint through nitrogen losses in soil and emissions in the form of N02, a potent greenhouse gas (evaporating into the atmosphere). The research is targeting significant sustainability gains in pasture production and will delivery practical ways to increase N efficiencies directly benefiting farmers in pasture-based dairy regions across Australia.

The project has seen the establishment of four new farmlets (or mini farms) to research strategies for reducing reliance on synthetic fertiliser and its impacts under ‘real farm’ conditions.

During the open day, participants received the opportunity to learn about the farmlet work and the research behind it.

Attendees heard about how nitrogen (N) work is focusing on maximum yield with minimum N inputs. N use has increased in the last 10 years from 100 kg N/ha/year during the 2010/11 season to 180 kg N/ha/year in the 2020/21 season.

Previous work in Dairy HIGH examined the N use requirements of all ryegrass varieties under glasshouse conditions. This showed that N requirements from the very first ryegrass variants from the 1940s through to the current variants is no different. What is different is the amount of dry matter produced by the plant; meaning that more nitrogen is needed now than what was used in the 1940s.

Dairy HIGH 2 is also investigating varying levels of N use within a farming system and what that means for the species sown in the paddock. For example, normal pasture mix for southern Australia is 20 per cent clover with 80 per cent ryegrass.

It is looking at the standard mix with current N level use; the standard mix with 150 kg N/ha/year based off what is currently being regulated within New Zealand; different mix with 30 per cent clover and 40 per cent ryegrass and 30 per cent plantain with 150 kgN/ha/year; and mixed species sward with minimal nitrogen input.

It is hoped that this research will demonstrate the impact that reduction in nitrogen use can have on a farm system and pinpoint the highest yield achievable with reduced nitrogen levels.

Visit climate and environment, and the Dairy HIGH 2 project for more information about programs that are helping dairy farmers.

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