Nitrogen
fertiliser has become a seemingly indispensible input for many modern dairy
farms. But how profitable are nitrogen fertiliser
decisions?
A new national
project ‘Dairy Nitrogen for Profit’, funded by the Geoffrey Gardiner Dairy
Foundation and Department of Primary Industries Victoria, is about to improve the
agronomic and economic basis for nitrogen fertiliser decisions on dairy pastures.
The
project involves the ‘who’s who’ of scientists working in nitrogen fertiliser
management on dairy farms from Victoria, Tasmania and Western Australia, and
Australia’s leading dairy farm economist, as well as staff from major
fertiliser and dairy companies.
According
to Dr Cameron Gourley, Senior Research Scientist and Project Leader with the DPIV
at Ellinbank, the issue is critical to dairy farm productivity. “Increased milk production on Australia dairy
farms over the past 2 decades has been largely driven by increased use of nitrogen
fertiliser and imported feeds”, he said.
“With anticipated increases in fertiliser prices, better decisions about
nitrogen inputs will be critical to the profitability and sustainability of
dairy farm businesses.”
Australian
dairy farmers are using between 4 and 10 times the amount of nitrogen
fertiliser compared with what they did 20 years ago. This equates to approximately
180,000 tonne of nitrogen fertiliser annually; costing around $200m, and on
average around $30,000 per farm each year.
While
nitrogen fertiliser is a key driver of dairy farm productivity, inefficient use
can results in diminished productivity, reduced profit and loss of excess
nitrogen to the environment. In a recent
national study on nutrient use on dairy farms, Dr Gourley and his team found
that the efficiency of nitrogen use (defined as outputs in milk and animals as
a proportion of inputs in feed and fertiliser) was on average less that 28%,
and the overall loss of excess nitrogen to the environment was often greater
than 225 kg of nitrogen per ha.
Such
low efficiencies and high surpluses are recognised worldwide as leading to
reduced economic performance, potentially adverse effects on cow performance,
and excess nitrogen in the environment. Consequently, dairy farmers are
increasingly being held scrutinised for the environmental performance of their
operations and better managing nitrogen is a major priority.
“More
sophisticated decisions on the use of nitrogen fertiliser inputs are required
as our dairy farms have intensified” Dr Gourley said. “The Dairy Nitrogen for Greater Profit”
project will develop improved tools for determining farm-specific production
and profit responses to nitrogen fertiliser use and make these available
through our partnership with industry.”
The
proposed approach acknowledges that there is not a single pasture production
response to a particular nitrogen application rate. The extra pasture growth from a nitrogen
fertiliser application and associated profitability will be influenced by many factors
such as soil temperature and moisture, rate and timing, pasture species
present, climate conditions, existing soil nitrogen supply and management
factors such as grazing pressure and feed supplementation.
“We
will make use of existing and new experimental data to develop improved
predictions of pasture responses to particular nitrogen fertiliser applications
in various situations.” Dr Gourley said. “The established pasture production
response functions for nitrogen fertiliser applications will then be analysed
along with new information from experiments on commercial dairy farms.”
According
to Professor Bill Malcolm, dairy farm economist and project team member “The
unique aspect of this project is bringing economics, and profit (marginal
return over marginal cost), to the fore; linked to improved predictions about
pasture responses to N fertiliser applications.
This is necessary for the continued competitiveness of Australian dairy
farmers.”
“There is a need to move from generalized
average and linear predictions of pasture production responses (e.g. 10 kg DM /
kg N applied on average, or, 1 kg N/ha/day of grazing) to advice that is
profit-based and tailored to the system/farm business” Professor Malcolm said. “This is particularly the case with nitrogen
fertiliser where the benefits are determined by important interactions between
parts of the farm system (e.g. feed production, stock policies and feed
utilisation).”
So
what will be the benefits? According to
Dr Gourley, “Australian farmers and their advisors will be more confident to
apply nitrogen fertiliser knowing that their own specific pasture and farm
characteristics are considered in the recommendation and that the best
available scientific information is being applied.” “Dairy farmers will be able to increase
profitability without wasting nitrogen fertiliser.” “This will in turn result in improved
nitrogen use efficiency, and a reduction in nitrogen losses from dairy farms to
ground water, waterways and the atmosphere.”
The
project has widespread support from the Geoffrey Gardiner Dairy
Foundation, Department of Primary
Industries Victoria, Department of Agriculture and Food WA, Tasmanian Institute
of Agriculture, the Fertiliser Industry Federation of Australia, Incitec-Pivot
Limited, Murray Goulburn Limited and Fonterra Limited.
