Whenever he ploughed his fields, Norman Dunne was used to the company of birds. On his farm in Co. Meath, he would drive his tractor up and down the land while the plough churned up the soil. Juicy earthworms would find themselves exposed to the air; hovering above them were crows and seagulls who were ready to pounce on the feast below.  

It's a scene that Norman’s father, Michael, experienced too. Back in his time - in the 1960s and 70s - there were so many birds following the tractor that he would have to wear a hat to stop all the bird poo falling on his head.  

But a few years ago, Norman noticed that the birds had all but given up. What was the point if there was nothing in the soil to eat? It was then that Norman knew that something wasn’t right with his land. "It was just hard work, and we needed heavier machines - bigger machines - and more power," he said. "And it really got me thinking that something really is askew here. We shouldn’t need to do all this to get it right."

He used a spade to scoop out a patch of soil, but he didn’t see much. It was then that Norman decided to do something to bring the life back to his land. He asked other farmers what they were doing, and informed himself by reading up on the science of soil biology. It was the start of a journey that has revolutionised how Norman farms, and a significant part of this change has been to reduce his use of synthetic nitrogen.

For something that is essential for life, it’s hard to believe that nitrogen can also be so very damaging. It’s a magic element that stimulates growth - throw a bit on your lawn and it’ll grow like billy-o - but too much can cause serious problems.

"Nitrogen should be in the forefront of everybody’s mind, in my opinion," says Dr. David Kelleghan of Teagasc. "Everybody should be aware of nitrogen as an issue, and it’s contributions to ecological impacts, human health and climate change."

Nitrogen comes in many forms - ammonia, nitrous oxide, nitrate and nitrogen dioxide - and scientists say it’s polluting our local waterways and soils, our air, our habitats and causing problems for our health. Nitrous Oxide is a greenhouse gas that contributes to the depletion of the ozone layer.

It is much, much more potent than carbon dioxide, with one study suggesting its 300 times as powerful. Simply put, we have too much nitrogen than our land can cope with, prompting calls for its use to be dramatically reduced. 

It’s a story that started back in 1909, when a German engineer called Fritz Haber discovered a way to pluck nitrogen from the air and turn it into synthetic nitrogen that farmers could use as a powerful fertiliser to boost crop growth.

Until that time, the only way to 'capture’ nitrogen was to plant crops that could do the job for you. The results with synthetic nitrogen were immediate, and its use has kept us all well fed for over a century.  It’s thought that without synthetic nitrogen, half the world’s population wouldn’t be alive today. 

When it comes to nitrogen pollution, the modern way we farm is part of the problem. According to the Teagasc and the EPA over 90% of nitrous oxide emissions in Ireland comes from agriculture and our intensive grass-based dairy system is widely dependent on nitrogen to ensure that enough rye grass is produced to feed the cows. Too much of it is in the system, and it’s thought that up to 70% of it is wasted into the surrounding environment.

 "Our losses are way too high," says Mike Walsh of Waterford Institute of Technology, who has been studying ways for farmers to cut back on nitrogen use. "We are losing too much to the environment to our water and groundwater.  And that’s having an effect, even down to soil bacteria."

Another form of nitrogen is ammonia, an air pollutant. The EPA report that 98% of ammonia emissions in Ireland come from agriculture. In 2016 - for the first time - Ireland exceeded the legally-binding EU limits for ammonia. And the trend has continued upward. Ammonia can suffocate species such as lichens, and combines with other air pollutants to form tiny particles called "PM 2.5" which are known to cause respiratory and heart problems when inhaled.  

Norman has made an effort to only use as much nitrogen as his crops need, but no more. Waterways border his farm, and he wants to ensure that the water runs clear without any nitrogen pollution. In order to do this, he invested in a machine that lets him melt a form of nitrogen, called ‘urea’, into a liquid that he can then carefully spray on his crops.

"It’s far more efficient," says Norman. "It’s not evaporating or it’s not washing away, so it’s targeting exactly where we want to put it, when we want to put it.  So it’s going directly to the plant, as opposed to anywhere else". 

He has also started to sow crops that naturally pull nitrogen from the air into the soil, making it more fertile without the need for vast quantities of synthetic nitrogen.  "I’m trying to tap into that naturally," he says. Alongside this, he has reduced how much he ploughs his land, which helps the soil health.  

His efforts have paid off.  Last year he reduced his synthetic nitrogen use by 5%, and he aims to increase this by 10% this year. He has saved money and enjoys his role as a farmer more than ever. 

"It’s made farming more interesting," he says. "It was kind of becoming a bit of a chore to be honest with you before that.  I definitely have more control over what I’m doing now. It’s a joy to see the benefits of what’s going on around us as well."

Watch Ear to the Ground tonight at 7pm on RTÉ One. #ettg