What UK dairy farmers can learn from Dutch ‘nitrogen crisis’

Scientists in the Netherlands are developing ways dairy farmers can reduce greenhouse gas emissions using methods that could also benefit UK milk producers.

It follows calls by the Hague government for a 50% cut in nitrogen emissions by 2030 – a target that Dutch farmers say threatens to drive them out of business, destroying their livelihoods and breaking up rural communities.

Dairy farmer Herman Miedema milks 175 cows across some 100ha of grass and maize silage just outside the small village of Vyns, in the heart of Friesland province – the dairy capital of the Netherlands.

See also: Joint land ownership allows Dutch milk producer to extensify

Mr Miedema is already reducing emissions. He installed a curved slatted floor system in 2009, so slurry and urine are stored immedately rather than left exposed to the elements, where they would volatilise.

He is also grazing cows outside for 180 days annually, reducing the amount of crude protein in feed rations and diluting manure with water before spreading it on the fields. But it is not enough. “We are being asked to do more – much more.”

One of the world’s most densely populated countries, the Netherlands is home to about 16,000 dairy farmers milking some 1.57 million cows.

Dutch agriculture is responsible for about half the country’s greenhouse gas emissions.

The Dutch government requires farmers to have a permit to farm.

Mr Miedema is one of the lucky ones; he still has his permit. But the Dutch Supreme Court has declared the permits of 3,000 livestock farmers invalid, throwing their future into doubt.

Permit predicament

Those 3,000 farmers find themselves in a nitrogen crisis. They are unable to invest in their businesses because the banks won’t lend them money. But they can’t sell-up either because few people want to buy a farm with an invalid permit.

To help farmers, the government has earmarked €25bn (£22bn) to halve nitrogen emissions from agriculture by the 2030 target. Proposals include paying dairy farmers to quit the industry.

Trinke Elshof, of the Dutch farmers union (LTO), says a 40% reduction in nitrogen emissions is possible. But a 50% reduction is a step too far, she argues – an impossible goal for the dairy sector.

“The government is focusing purely on nitrogen emissions. But we think they should look more broadly.

“We need a total package – reductions, yes, but also solutions such as innovation and other on-farm measures.”

Scientists at the Dairy Campus research centre – part of Wageningen University – agree that innovation has a big part to play in reducing emissions in a way that could benefit farmers, consumers and the environment.

Founded in 2011, the centre is undertaking an increasing amount of research into emissions reduction, including innovative nutrition and grazing techniques, manure and slurry management, housing, and animal health and welfare.

The centre at Leeuwarden includes 500 dairy cows across 350ha of land.

Wageningen livestock scientists conduct high-tech, applied research and groundbreaking experiments across the entire dairy chain.

Data first

“This is not a farm – milk is a by-product of what we do,” says Dairy Campus managing director Kees de Koning.

“Our core business is research – our cows produce data – lots and lots of data and information. We need cows to do that to help shape a future for Dutch dairying while reducing greenhouse gas emissions.”

Dairy cows in parlour at Dairy Campus in the Netherlands

© MAG/Johann Tasker

When it comes to cow diets, Dairy Campus researchers have already shown that a 1g reduction in crude protein content can reduce ammonia emissions by 1% without a corresponding drop in milk yield, so long as cow management is high.

They have already reduced dietary crude protein content from 165g to 150g/kg dry matter, cutting ammonia emissions by 15% without any detrimental effect on cows with a 10,000-litre lactation. Their aim is to see how low they can go.

“We have a saying: what doesn’t come in, doesn’t come out,” says scientist Harmen van Laar.

“It is about adjusting the ration to reduce emissions without affecting milk output, cow health and welfare or fertility.”

Dairy Campus scientist Bert Philipsen has been investigating the effect of grazed grass and silage on emissions. Silage contains more crude fibre, but fresh grass can help reduce emissions of enteric methane, he says (see “Ways to cut dairy emissions”).

Feeding fresh grass is a cost-effective way of reducing emissions, says Dr Philipsen.

“You don’t have to invest in any additional machinery or technical equipment, and some processors will pay a 1-2cent/litre premium on the milk produced.

Feed suppliers and other farm input suppliers are using this knowledge to help farmers improve cow management out in the field.

They include Judith Mensink, a nutrionist with the feed company Agrifirm.

“We are delivering feeding advice – encouraging farmers to graze more efficiently, add supplements to their rations where appropriate and reduce crude protein content to cow diets where they can.

“But it’s not just about the ration, it’s also about feed management. It’s about cow comfort and health.

“You want your cows to give as much milk as possible, and that means ensuring they are healthy, whether they are feeding indoors or grazing outside.”

People and planet

Despite some success, farming campaigners argue that the government is continuing to prioritise the environment at the expense of people.

And they warn that putting farmers out of business will decimate rural communities.

“There is a lot of pressure on farmers to just go away,” says Sieta van Keimpema, of the Dutch Farmers Defence Force.

“Our government wants to buy out farmers, and if you do not do it voluntarily, they will push you out. It’s going too far.”

Like the farmers she represents, Ms van Keimpema believes innovation is the answer.

“It’s the reason that we are not milking cows by hand anymore. And we shouldn’t forget, that every year there are more people on this planet. Everyone is a consumer, and that is part of the problem.

“If there was no innovation, no one would have a bicycle or a car or would fly. It’s unfair to ask farmers to turn the clock back 200 years while letting everyone else consume whatever they want.”

It is an argument that has gone beyond farming.

The Farmer-Citizen Movement (BBB) political party has surged in popularity – winning some 20% of the vote in last month’s provincial elections.

BBB politician Femka Wiersma says the shock result shows that the government needs to listen to the people.

“Trust in the government is at an all-time low,” she says. “We need a party that can regain that trust, and a long-term policy for Dutch farmers.”

Ways to cut dairy emissions

Graze grass

Grass and grazing have the potential to reduce both ammonia and methane emissions.

Methane emissions are lowest with full grazing, compared to grass silage and zero-grazing systems.

A further study is investigating whether grass silage from first, second and third cuts lead to a different quantity of methane emissions.

Weekly milk samples are being taken to determine milk fat and protein content, with feed samples collected from silage pits of grass cut at different times.

Better floors

Emissions-reducing floor systems enable rapid drainage of urine as well as sealing of the floor.

Using this system, slurry pit emissions have been as low as 6kg of ammonia an animal a year.

Dairy Campus researchers are testing a new system they believe could reduce ammonia emissions to just 3kg an animal, without gas forming in the slurry pit below and with separate manure flows for further valorisation.

Feed additives

Methane inhibitors have significantly cut dairy cow emissions in the Netherlands.

The reduction varies from 27-40% a cow, depending on the animal’s ration and the amount of inhibitor administered.

A quarter of a teaspoon of the inhibitor Bovaer daily per cow has reduced emissions by an average of 30%.

Tests were conducted across three different configurations of grass silage and maize silage diets.

There are also indications that certain types of seaweed can inhibit the formation of methane during the digestion of feed.

Urine and manure

By encouraging cows to urinate in a special “toilet” while eating concentrate, the urine does not end up in the solid manure, and considerably less ammonia is formed.

The toilet is actually a walk-through concentrate feed box that stimulates the cow to discharge urine.

It detects urination and then collects, drains and stores it away from the manure. Cows voluntarily enter and leave the box.

Scientists say there is no indication that the welfare of the cows is compromised during this process.

They say there is another major advantage, too – the pure cow urine is rich in potassium and nitrogen and can be used as a fertiliser substitute.

Explore more / Transition

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