By Jane Powell

One of the interesting angles to come out of the Brexit debate is the need for local cooperation. The balance between economic activity and care for the environment on which it depends is a difficult one to maintain, and top-down regulation is not enough on its own. But what does that look like? A new project in Pembrokeshire is trialling a partnership model to manage fertilizer pollution, and offers an intriguing new possibility.

Synthetic nitrogen fertilizer is as much a part of modern life as the car and the television, just much less visible. Chemical companies have been producing nitrates since the Second World War, when the factories that had been making explosives were turned to peacetime uses, and it’s now a cornerstone of modern farming. Applied judiciously, it speeds up plant growth and allows farmers to make the most of a short growing season.

But it comes at a cost. For one thing the manufacturing process requires a lot of oil, as nitrogen and hydrogen have to be combined at high temperatures and pressure. And because nitrates are highly soluble, they are easily washed into rivers where they cause aquatic plants to grow too fast, upsetting the ecological balance and damaging both wildlife and fisheries. This is a particular problem in Pembrokeshire, where concerns about nitrate pollution in the river Cleddau and Milford Haven have led to calls to declare the area a Nitrate Vulnerable Zone (NVZ) under EU law.

This would mean that farmers would be obliged to cut their fertilizer use, and also face restrictions on how they can spread nitrogen-rich slurry, or manure, on the land. They would for instance have to store it if the land is waterlogged, waiting for dry conditions so that it is absorbed into the soil rather than running off into rivers. Financial margins in farming are tight, and farmers say that cutting production or investing in bigger slurry tanks would put some of them out of business.

Also, it isn’t just cows that produce manure. Humans do too, and sewage plants are responsible for a fair proportion of both nitrogen and phosphorus pollution in the Cleddau. The river catchment is now ‘full’ of nutrients, making further economic development unacceptable.  Clearly, nutrient pollution needs to be reduced, but this is a problem caused by human activity in general, and it doesn’t seem fair to hold farmers solely responsible. Could there be a better solution?

At Pelcomb Farm near Haverfordwest, farmer Mike Smith and soil expert Jon Williams spread soil analysis reports out on the kitchen table. Jon points out the 2013 analysis for one particular field, which shows an imbalance between magnesium and calcium. Magnesium is important, he explains, because it is an essential part of the chlorophyll molecule. Without enough magnesium, crops cannot photosynthesize efficiently, however much nitrogen they are fed.

Magnesium also however has the effect of binding soil clay particles very tightly, and needs to be counterbalanced by calcium, which produces a looser soil structure, good for aeration and drainage. By 2017, applications of magnesium have brought the soil back into balance and increased the efficiency of nitrogen use.

By this and other adjustments, such as avoiding compaction with heavy machinery, Mike has been able to reduce his use of nitrogen fertilizer on his intensive dairy farm to a third of what it was, saving money and protecting the quality of the river water. He also keeps a careful eye on his slurry.

“For a farmer, slurry is a valuable resource, full of nutrients. We don’t want to lose it to our rivers! So we do a soil analysis before we plant, say, a cereal crop, and we analyse the slurry as well. That way, we can apply the right amount to the land and cut down on artificial fertilizer too.”

Rather than the NVZ, Mike wants to see a voluntary scheme, where farmers are accredited in rather the same way that a beach gets a Blue Flag for its water quality.

The First Milk dairy cooperative of which Mike is a member has already shown how farmers can work together to clean up their act. In 2005, Welsh Water served notice that they would no longer treat the effluent from First Milk’s Haverfordwest cheese factory at their sewage plant, because they needed the capacity for new housing development.

After prolonged negotiations between First Milk and Natural Resources Wales, an agreement was reached in 2011 whereby treated effluent from the cheese factory could be discharged directly into the Cleddau, providing that the member farmers offset these nutrients by changes to farming practices further upstream.

Building on this success, there is a new initiative to introduce a nutrient trading scheme which would allow farmers to be rewarded for better management of nitrates. Any new housing development, hotel or factory will put extra pressure on the Cleddau catchment, and so needs to come with a plan to ensure that there is no net increase in pollution.

The EU funded project BRICs, or Building Resistance into Catchments, is working on a trading scheme that would allow farmers to sell credits to developers, thus spreading the cost more fairly. It would also introduce a culture where farmers are seen as business leaders, rather than offenders to be policed.

BRICs is necessarily a partnership project. It works with a wide range of organizations, including land managers, industry, conservation organizations, the farming unions, Welsh Water, farming cooperatives, local authorities, RPK ADAS and Natural Resources Wales.

There’s a lot at stake. Not only is it important to open up new capacity for industrial and housing development in the area, but good farming practice is of vital importance in itself, and farmers need to be properly supported to do this.

Out in the field at Pelcomb, Jon gets his spade out and digs a hole. The turf comes out easily, and the soil underneath is dark, sweet-smelling, loose and crumbly, with a few stones, worms and a healthy mesh of grass roots. “This is how it should be,” he says. “Soil is a living thing, full of bacteria, fungi and worms, and it wants to be in balance”.

He explains how natural processes in the soil produce 80% of the nitrogen a crop needs, and artificial fertilizer often does more harm than good. Organic farmers avoid it altogether, relying on crop rotations and careful manure management to do the job.

“Welsh soils contain plenty of organic matter because they’ve been under grass and livestock for so long. If we can manage our soils and manures properly, we can cut our dependence on synthetic nitrogen, build soil fertility and go a long way towards reducing the carbon footprint of Welsh agriculture,” he says.

The Pembrokeshire experiment will see if a fairer system of sharing the costs of good soil management – and therefore of food production – can help build a culture of cooperation and trust that will benefit the natural world on which everything depends.

Jane Powell is the Wales coordinator of LEAF Education and is working on a case study of nitrate trading for use in secondary schools. She also writes at www.foodsociety.wales.

Image: algae covering the mudflats at Garron Pill on the eastern Cleddau, by Sue Burton.