An Irishman's Diary

I was driving up to Cavan last Saturday when a strange thing happened in the back of the car. Namely, my eight-year-old son put down his hand-held computer game long enough to look around him.

At any other time, this would require a house fire, or equivalent emergency. But before I had time to wonder what was wrong with him, he curled his nose up in an expression of extreme disgust and said: "Eeeuw! The smell of the countryside!"

I had to admit he had a point. It is now three weeks into slurry-spreading season in the Border counties, and the action is clearly hotting up. The odours of organic fertiliser were as frequent a feature along the N3 as traffic tailbacks - a correlation you noticed when trying to drive through the affected areas as quickly as possible.

Even so, taking offence on behalf of the countryside, I thought about giving my city-slicker son a lecture on where food comes from - including some of the more inconvenient facts that contribute to putting milk on his Cheerios or salami on his pizza.

But not even slurry could distract him from the PSP that long. And besides, a rural upbringing doesn't render you indifferent to the smell of slurry. I still can't stand it either.

At the risk of sounding like a wine critic, I would say that, as agricultural odours go, the bouquet from pig manure is definitely the worst. Cattle dung has an almost pleasant "nose" by comparison (with hints of buttercup, daisy, and wild garlic). And of course equine effluent is the Chateau Margaux 1967 of natural fertilisers - which is probably why the Dublin Horse Show has lasted longer in Ballsbridge than the old Spring Show, with its wider range of livestock.

But as I nearly explained to my son, the smell of slurry is a necessary evil. Those displaced urbanites who complain so bitterly about it should consider it a tax on rural life, just as traffic, noise, and higher beer prices are taxes on city living. After all, like Scottish football players, they even get a winter break now, thanks to the Nitrates Directive's close season on spreading (completely illogical, by the way, in a winter as dry as the one just past).

All the new one-off houses in the countryside have exacerbated the culture clash, unfortunately. The Fertiliser Association of Ireland's Code of Good Practice recommends that spreaders should maintain manure-free "buffer" zones near all watercourses. But buffers between farms and their non-agricultural neighbours are a discretionary matter. Some farmers are more enthusiastic about marking their territories than others. And anyway, there are no buffer zones in the air. When the wind is blowing, whole towns can suffer, never mind ribbon-development bungalows. Those are the breaks, as I say.

Could this drawback of country life ever disappear? I had high hopes a few years ago when scientists in Canada started working on something called the "Enviropig". As you might guess, this is a genetically modified animal, with all the ethical issues that involves. But as they sought to change the nature of pig manure, the scientists were on moral high ground, because their main aim was to eliminate the phosphorous that causes so much damage to rivers and lakes.

They succeeded too. By taking DNA from a mouse, they enabled the Enviropig to produce a phosphorous-digesting enzyme in its saliva, cutting the amount of the chemical excreted by 60 per cent. Getting the modified piggy to market has been a more complex matter, however. And the bad news anyway is that reducing its phosphorous content did nothing to improve the manure's smell. For now at least, the Perfumopig remains only a dream.

Of course, reducing smells does not require genetic modification. There are treatments available that leave the animal alone and deal solely with the back-end product - biodigesters, for example, and even catalytic converters.

The latter category includes a French product that, according to its website, makes it possible for slurry "to discharge a gas completely purified from ammonia, methane, and oxides of nitrogen and sulphur". The process "does not damage the ozone layer" using a catalyst in a solution that oxidises the "volatile and malodorous sulphurated compounds. . .into heavier, non-volatile compounds that remain in the liquid".

Which sounds like good news. And speaking of the ozone layer, there may be hope from that front too. The current imperative to reduce methane emissions from livestock - one of the bigger contributors to global warming - is inspiring research into new animal foodstuffs that might have a knock-on effect in odour reduction.

But you win some, you lose some. The same concern with climate change has seen the value of bio-fuels soar recently, making animal meal more expensive than ever. One farmer I know of is now losing €21 on every pig he sells. With margins like that, spending money to improve the smell of manure is not a priority.

In short, there seems little immediate prospect of slurry as we know it becoming a threatened faeces (sorry). So my advice if you're a city person with a sensitive nose is to avoid the countryside for the rest of February, by which time the initial spreading frenzy - the start of the growing season - will be over. It will probably be safe to venture out by Easter. Just remember to be back before the first cut of silage, in early June, when the sequel to Attack of the Muck-Spreaders begins.