|
ABC NEWS
August 11, 2022
By
Angus Verley
Nitrogen use in the spotlight as
grain industry pushes to reduce greenhouse gas emissions
Luke Batters is using this blend of
green waste and manure as a partial substitute for synthetic nitrogen
fertiliser.(ABC
Rural: Angus Verley)
With several governments around the world
pursuing limits on nitrogen fertiliser use in agriculture, how would
farmers adapt if the Australian government took a similar approach?
Key points:
-
Fertiliser production and use is responsible for more than half of
the greenhouse gas footprint of the national wheat crop
-
Nitrous oxide emissions come from the volatilisation of nitrogen
fertilisers like urea
-
Volatilisation can be minimised through management, but synthetic
nitrogen is hard to replace in cropping systems
In broadacre cropping,
fertiliser production and use accounted for 58 per cent of the
Australian wheat crop's greenhouse gas footprint in the past five
years, according to the Department of Agriculture.
Of that, 31 per cent
occurred on-farm, a large part of which came from the use of nitrogen
fertiliser.
The greenhouse gas nitrous
oxide comes from the denitrification of nitrates in soils, and the
pollutant ammonia comes the volatilisation of nitrogen fertilisers.
Nitrous oxide is almost
300 times more potent than carbon dioxide.
James Murray is senior
research manager with the Birchip Cropping Group.
He said there
were products available to slow the volatilisation process, which
occurs when nitrogen is applied to a crop and there is insufficient
rainfall following application to break it down.
James Murray says regardless of
motivating factors, more efficient fertiliser use will benefit both
the environment and the hip pocket.(ABC
Rural: Angus Verley)
"There are a couple of
products on the market — one is a urease inhibitor, which reduces that
volatilisation risk by slowing that release when you apply if you
don't get follow-up rainfall relatively quickly," he said.
"The other one is a
polymer coating, which slows the release of nitrogen quite
significantly.
"But the challenge with
them is they're not necessarily cost-effective to utilise, with the
urease inhibitor retailing for about $50 a tonne on top of your urea
cost, so it opens up a question about how cost effective that is in
the farming system."
Mr Murray said whether or
not farmers used a urease inhibitor, there was significant value in
getting nitrogen application right and minimising volatilisation.
"We talk a bit about the
four Rs — so the right rate, the right product, the right source and
the right timing, which at the end of the day will have significant
benefits for production, and if we're reducing our greenhouse gas
footprint at the same time, that's a bonus," he said.
Urea can release nitrous oxide into
the atmosphere.(ABC
Wimmera: Andrew Kelso)
Countries including New
Zealand, Canada and the Netherlands are pursuing limits on fertiliser
application to reduce emissions, which Mr Murray says is a
consideration for farmers here.
"There are considerations
around market access and potential future mandates on how things are
utilised," he said.
"I think there's a great
opportunity for the Australian grains industry to be ahead of the game
on this stuff, whether it's for market access or potential mandate
considerations.
"In terms of improving
the way we use our inputs, the biggest benefit is to the bottom line
in terms of improving crop production."
What are the alternatives?
Some farmers are trialling alternatives to
synthetic fertiliser under the broad umbrella of "regenerative
agriculture".
Among them is Luke
Batters, who farms with his family near St Arnaud in western Victoria.
"Our operation is largely
a synthetic-based system and our use of synthetic fertilisers and
chemicals has increased substantially," he said.
"I was working out of
agriculture for seven years and when I came back to the farm I had a
different mindset and so we're trialling a few different things around
inputs, in terms of how different carbon and biological and
chemistry-based inputs affect the system."
Mr Batters is trialling
alternatives like compost, manure, seaweed and vermicast, which is a
mixture of products, including worm castings.
"It wasn't until I
started doing this trial work that I realised how reliant we were on
nitrogen as a synthetic input," he said.
Nitrogen-rich sheep urine patches
are growing much better than surrounding areas on Luke Batters's farm.(ABC
Rural: Angus Verley)
What are the problems?
Mr Batters said while he
thought his trials were otherwise healthy, they were severely lacking
in nitrogen and he had not been able to make up the shortfall with the
alternatives he has used.
"I went largely cold
turkey and stopped using synthetic fertilisers and it's been quite
stark, the difference between applied synthetic fertilisers and no
synthetic fertiliser and having to rely on those alternatives," he
said.
"These things will work
in a system once the biology gets up and going, but because our
current system is so depleted of biology, it really hasn't taken
off."
Mr Batters said he had not
achieved the results he was hoping for but he would persist.
"If there are regulations
in the future around what we can and can't do and we haven't got an
alternative we'll come unstuck," he said.
Green Play Ammonia™, Yielder® NFuel Energy.
Spokane, Washington. 99212
www.exactrix.com
509 995 1879 cell, Pacific.
exactrix@exactrix.com
|
