Castledockrell in Co Wexford has become part of environmental folklore. Depending on what side of the environmental debate you are on, the area demonstrates that farming is capable of being carried out with minimal effect on the overall environment.

On the other hand, the argument has been made that even a crop such as spring barley, grown extensively in the area over a long period, should have the nutrients permitted to be used in its production curtailed.

Last week, I spent a very instructive number of hours in the area as part of a group from Tillage Industry Ireland, trying to absorb the key messages as the nitrates debate becomes increasingly polarised and the role of the Agricultural Catchments Programme comes increasingly into focus.

With about 2,500 acres, the Castledockrell site is pretty well average for the six catchments areas around the country.

The programme is not cheap to run, with 23 scientists, advisers, technologists and technicians involved full time.

The difference is that the Castledockrell site is the only one that is predominantly in spring tillage, and with no autumn growth, the main problem is nitrate seeping into the ground water after the harvest.

The effect of this is not seen in the actual river Slaney itself, which is recognised as having excellent quality water, but in the estuary.

But even in the estuary, the water is of a quality far better than the EU drinking water standard, but below that required “for ecology”.

Catch crop

Excess phosphorus is not a problem, so the emphasis is on nitrates. The logical response to the lack of autumn growth is to grow some form of catch crop, and these have been clearly shown to have recovered nitrogen from the soil and dramatically reduced nitrogen leaching.

So far, so good, but a number of key questions arise. First, if nitrate concentrations in the estuary are well below drinking water requirements but above some theoretical ecological level, then how far do we go in meeting theoretically desirable objectives regardless of costs? Life is a series of trade-offs and compromises.

Second, if catch crops are shown to significantly reduce nitrate leaching, then how far should we encourage them? The ideal would seem to encourage the traditional practice of keeping sheep on the catch crops and reassess the mandatory new lieback regulations.

The worst outcome would be a regime that imposes unnecessary production reductions in pursuit of environmental outcomes that are not demanded of any of our international competitors and would jeopardise farm livelihoods and rural community well-being.