A large dairy farm in Northern Ireland is trailing a new system that reduces ammonia emissions while producing liquid nitrogen fertiliser at the same time.
This concept, developed by Norwegian company N2 Agri, involves passing manure or digestate through a plasma reactor to produce the liquid nitrogen fertiliser.
This process, says the company, will ultimately save farmers up to 20pc of their artificial fertiliser costs, and reduce their ammonia production levels.
Although the concept has moved beyond the prototype stage, it is still being tested around the world; one on a pig farm in Denmark and the other on a 650-cow dairy farm near Templepatrick in Co Antrim.
This farm is run by Robin Bingham and his son George, who installed a biogas plant a year ago that produces electricity and supplies it into the national grid. In total, the farm has 1,200 cows and runs a zero-grazing system, where the fresh grass is harvested and delivered to the cows daily.
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The plasma reactor was installed at the farm two months ago on a trial and is already producing liquid nitrogen, which has been spread on test plots at the farm.
N2 Agri says its goal is to fundamentally improve the global food production by enabling farmer to produce their own fertiliser from manure, air and renewable energy.
The company says the savings on artificial nitrogen costs would cover the cost of the plasma reactor in six or seven years.
The technology involves the plasma reactor fixing nitrogen from the air and adding it to the manure. This causes a reaction that stops ammonia losses as well as emissions of other greenhouse gasses – and it removes bad odour.
The system increases the nitrogen content in the manure, transforming it from a waste problem into a high-value fertiliser.
Henk Aarts, N2 Agri business development director, says: “Our objective is to empower livestock farmers through introduction of a low-cost, scalable fertiliser production on the farms.
“Our ultimate goal is to substitute chemical fertilisers with fertiliser produced locally on the farm from, manure, air and renewable energy.
“We can also upgrade biogas digestate to a higher-value fertiliser with our technology.”
The company has plans to embark on more trials further afield in places like South Africa.
Mr Aarts adds: “We are not in the phase of selling machines yet, but want to show our plasma reactor and explain the working principles to the stakeholders.
“Our reactor is not fully developed, but we want to test it under farm conditions in an early stage to get experience with different types of manure and biogas digestate and to do field trials on different crops, which on the Bingham farm are grass plots.”
The key argument to convince farmers to use this plasma reactor is to explain how they are losing so much nitrogen from their livestock and slurry which is later supplemented by artificial fertiliser spread on the ground.
In fact, there is 2.13 million tonnes of ammonia lost on European livestock farms each year – a huge loss of potential fertiliser.
One of the founders of N2 Agri is Rune Ingels, a chemical engineer who spent almost 30 years working in the fertiliser industry, more recently with Yara, before resigning to embark on his own ideas.
He explains how farmers lose nitrogen and are forced to pay out for expensive artificial fertiliser.
He says: “We need above 95pc moisture content in the manure to make the system work. Slurry has 50pc free ammonia but digestate has around 70pc free ammonia.
“Just over 50pc of the total nitrogen available in slurry is lost before it can be spread on the ground. However, using our system we can make more nitrogen available for plants, which are also taken up quicker by the plants, increasing their growing rates and yields.
“There are some tweaks needed to the system the Binghams are using as it is primarily installed to test yields at the moment.”
George Bingham says the system interested him as it promotes environmentally friendliness.
“Using this plasma reactor system will help us achieve our goals of farming in a more environmentally friendly way while at the same time, sorting out my ammonia quotas,” he says.
“I see this as a potential game-changer across the world helping farmers get more from their farmyard slurry and saving them money.
“For me, reducing or even eliminating my chemical fertiliser bill is one of the main benefits of this system.
“The system has only been installed one month and we have already produced our own liquid nitrogen and spread it on some grass test plots to see if the theories of faster plant growth with higher yields are feasible.”
It is anticipated that a farm with 150 to 200 cows will need one 25kW plasma reactor; so a 600-cow herd would need three units. However, the reactors can be scaled, according to Mr Aarts.
“We can change the sizes of the reactor to suit the herd,” he says. “We don’t have exact prices as yet but I can tell you a reactor is cheaper than a milking robot and is the same size as one.”